Allow option of reading of files with prior releases (for 7_0_X)

Offline has committed to allowing HLT jobs running in an earlier release to read raw data files written in a later release.  This is currently prevented by a defensive check  that disallows reading products in a release prior to the release in which the product was created.  This pull request adds a configurable option "bypassVersionCheck" to bypass this check.  See
https://indico.cern.ch/event/299538/material/slides/1.pdf
for the XEB report in which this commitment is documented.
This pull request is for 7_0_X only.  It needs to be customized for other release cycles.