Fix error "array subscript outside array bounds"

Log file: https://cmssdt.cern.ch/SDT/cgi-bin/buildlogs/slc7_amd64_gcc11/CMSSW_12_1_X_2021-07-30-0900/CondCore/EcalPlugins
Error message:
```
/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc: In member function 'virtual bool {anonymous}::EcalFloatCondObjectContainerPlot::fill(const std::vector<std::tuple<long long unsigned int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&)':
  /data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:120:17: error: array subscript 1 is outside array bounds of 'TPad* [1]' [-Werror=array-bounds]
   120 |       pad[1]->cd();
      |       ~~~~~~~~~~^~
/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:112:28: note: referencing an object of size 8 allocated by 'void* operator new(std::size_t)'
  112 |       TPad** pad = new TPad*;
      |                            ^
  /data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:122:17: error: array subscript 2 is outside array bounds of 'TPad* [1]' [-Werror=array-bounds]
   122 |       pad[2]->cd();
      |       ~~~~~~~~~~^~
/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:112:28: note: referencing an object of size 8 allocated by 'void* operator new(std::size_t)'
  112 |       TPad** pad = new TPad*;
      |                            ^
/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc: In member function 'bool {anonymous}::EcalFloatCondObjectContainerDiffBase<nIOVs, ntags>::fill() [with cond::payloadInspector::IOVMultiplicity nIOVs = cond::payloadInspector::SINGLE_IOV; int ntags = 1]':
  /data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:273:17: error: array subscript 1 is outside array bounds of 'TPad* [1]' [-Werror=array-bounds]
   273 |       pad[1]->cd();
      |       ~~~~~~~~~~^~
/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:265:20: note: referencing an object of size 8 allocated by 'void* operator new(std::size_t)'
  265 |       TPad** pad = new TPad*;
      |                    ^~~~~~~~~
  /data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:275:17: error: array subscript 2 is outside array bounds of 'TPad* [1]' [-Werror=array-bounds]
   275 |       pad[2]->cd();
      |       ~~~~~~~~~~^~
/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:265:20: note: referencing an object of size 8 allocated by 'void* operator new(std::size_t)'
  265 |       TPad** pad = new TPad*;
      |                    ^~~~~~~~~
/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc: In member function 'bool {anonymous}::EcalFloatCondObjectContainerDiffBase<nIOVs, ntags>::fill() [with cond::payloadInspector::IOVMultiplicity nIOVs = cond::payloadInspector::SINGLE_IOV; int ntags = 2]':
  /data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:273:17: error: array subscript 1 is outside array bounds of 'TPad* [1]' [-Werror=array-bounds]
   273 |       pad[1]->cd();
      |       ~~~~~~~~~~^~
/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:265:20: note: referencing an object of size 8 allocated by 'void* operator new(std::size_t)'
  265 |       TPad** pad = new TPad*;
      |                    ^~~~~~~~~
  /data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:275:17: error: array subscript 2 is outside array bounds of 'TPad* [1]' [-Werror=array-bounds]
   275 |       pad[2]->cd();
      |       ~~~~~~~~~~^~
/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/3f7c5ca595fd8634b26b919adc27f210/opt/cmssw/slc7_amd64_gcc11/cms/cmssw/CMSSW_12_1_X_2021-07-30-0900/src/CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc:265:20: note: referencing an object of size 8 allocated by 'void* operator new(std::size_t)'
  265 |       TPad** pad = new TPad*;
      |                    ^~~~~~~~~
```

CondCore/EcalPlugins/plugins/EcalFloatCondObjectContainer_PayloadInspector.cc

@@ -109,7 +109,7 @@ namespace {
 
       float xmi[3] = {0.0, 0.24, 0.76};
       float xma[3] = {0.24, 0.76, 1.00};
-      TPad** pad = new TPad*;
+      TPad** pad = new TPad*[3];
       for (int obj = 0; obj < 3; obj++) {
         pad[obj] = new TPad(Form("p_%i", obj), Form("p_%i", obj), xmi[obj], 0.0, xma[obj], 0.94);
         pad[obj]->Draw();
@@ -262,7 +262,7 @@ namespace {
       }
       float xmi[3] = {0.0, 0.24, 0.76};
       float xma[3] = {0.24, 0.76, 1.00};
-      TPad** pad = new TPad*;
+      TPad** pad = new TPad*[3];
       for (int obj = 0; obj < 3; obj++) {
         pad[obj] = new TPad(Form("p_%i", obj), Form("p_%i", obj), xmi[obj], 0.0, xma[obj], 0.94);
         pad[obj]->Draw();