Update Ecal Gain.xml for Sim10
Update Ecal ActiveToTotal parameter (7.66->7.20) for Sim10 Set L0Corrections to 1.00 as those parameters was actually never set for data taking
This updated Gain.xml condition can be propagated for all Run2 MC in SimCond, i.e. other (L0)gain parameters are consistent with data taken after June 2015