edmCheckClassVersion: disable for ROOT6 until ready

edmCheckClassVersion must be disabled and return 0 in order to
generate capabilities files in CMSSW.

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
Merge pull request #1427 from davidlt/disable-edmCheckClassVersion-for-root6

edmCheckClassVersion: disable for ROOT6 until ready