expand tar archives in user sandbox

[belforte]

if user sandbox contains a tar archive, expand it.
Solves dmwm/CRABClient#5198

[belforte]

do it now, so I close on requests for CRAB from Kevin.

[belforte]

relevant code is

CRABServer/scripts/CMSRunAnalysis.py

Lines 407 to 417 in f817752

	def extractUserSandbox(archiveJob, cmsswVersion):
	# the user sandbox contains the user scram directory files and thus
	# is unpacked in the local CMSSW_X_Y_X dir, but the cmsRun command
	# will be executed from the job working directory, so we move "up"
	# the PSet which is also in the user sandbox
	os.chdir(cmsswVersion)
	print(subprocess.getoutput('tar xfm %s ' % os.path.join('..', archiveJob)))
	os.rename('PSet.py','../PSet.py')
	os.rename('PSet.pkl','../PSet.pkl')
	os.chdir('..')

Note that all sandbox files will be placed in $CMSSW_BASE directory in the worker node

[belforte]

as already noted in the CRABClient issue, the plan is:

look for files whose name contains .tar. or ends with .tar or .tgz or .tbz

[belforte]

I got it wrong.
User's jobType.inputFiles need to be expanded in /srv (the current working directory when the application is run)
see: #7705

[belforte]

fixed via #7708