Mods for 7_0_X compatibility: make empty HcalUpgradeDigis, protect against missing CrossingFramePlaybackInfo
Modify inputTag type
Merge pull request #2491 from mdhildreth/PreMixing_mods_for_7_0_X_compatibility

Configuration/StandardSequences -- Pre mixing mods for 7 0 x compatibility
Merge remote branch 'origin/CMSSW_7_0_X' into CMSSW_7_0_X