[Bugfix] Allow for multiple ? in outgoing urls.

Without this fix urls that had multiple ? in them would drop sections
of the url since before there was an assumption of there only being one.

lib/http-proxy/common.js

@@ -141,7 +141,7 @@ common.urlJoin = function() {
       lastSegs = last.split('?'),
       retSegs;
 
-  args[lastIndex] = lastSegs[0];
+  args[lastIndex] = lastSegs.shift();
 
   //
   // Join all strings, but remove empty strings so we don't get extra slashes from
@@ -155,7 +155,9 @@ common.urlJoin = function() {
 
   // Only join the query string if it exists so we don't have trailing a '?'
   // on every request
-  lastSegs[1] && retSegs.push(lastSegs[1]);
+
+  // Handle case where there could be multiple ? in the URL.
+  retSegs.concat(lastSegs);
 
   return retSegs.join('?')
 };

test/lib-http-proxy-common-test.js

@@ -203,13 +203,13 @@ describe('lib/http-proxy/common.js', function () {
       expect(outgoing.path).to.eql('/forward/static/path');
     })
 
-    it('should not modify the query string', function () {
+    it.only('should not modify the query string', function () {
       var outgoing = {};
       common.setupOutgoing(outgoing, {
         target: { path: '/forward' },
-      }, { url: '/?foo=bar//&target=http://foobar.com/' });
+      }, { url: '/?foo=bar//&target=http://foobar.com/?a=1%26b=2&other=2' });
 
-      expect(outgoing.path).to.eql('/forward/?foo=bar//&target=http://foobar.com/');
+      expect(outgoing.path).to.eql('/forward/?foo=bar//&target=http://foobar.com/?a=1%26b=2&other=2');
     })
   });