modified for CMSSW_7_2_X and Sherpa 2.1.1
Merge pull request #799 from pmillet/cmssw_7_2_X_sherpa_2_1_1

Cmssw 7 2 x sherpa 2 1 1
Merge remote branch 'origin/IB/CMSSW_7_2_X/stable' into IB/CMSSW_7_0_X/stable