LHE wf: temporary fix for IB

- force DYToll01234Jets_5f_LO_MLM_Madgraph_LHE_13TeV to be executed - /GEN input does not exist yet

- recycle command pointing to LHE /GEN dataset will need be put back after 74pre1 has made relvals

 -with respect to https://github.com/cms-sw/cmssw/pull/6692 : if cvmfs is available on the IB nodes, the 6 new LHE wf's will work fine ; if not, cvmfs will be the origin a new type of crash