added CMSSW_7_1_ROOT6_X for slc6_amd64_gcc481
Add das cache for runTheMatrix workflows.

See also cms-sw/cmssw#2420.
Merge pull request #409 from degano/das-cache

Add das cache for runTheMatrix workflows.
Merge remote branch 'origin/IB/CMSSW_7_0_X/stable' into IB/CMSSW_7_0_X/stable
Merge remote branch 'origin/IB/CMSSW_7_1_X/stable' into IB/CMSSW_7_0_X/stable