Allow option of reading of files with prior releases (for 6_2_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 6_2_X only. It needs to be customized for other release cycles.