switch pileup to 35 for relvals, both 25ns and 50sn; as agreed here: https://indico.cern.ch/event/342011/
Merge pull request #5591 from franzoni/setPUforRelvalsTo35-CMSSW_7_3_X_2014-09-26-0800

Configuration/PyReleaseValidation -- switch pileup to 35 for relvals