vldb_check: print vlentry file offsets

vldb_check: print vlentry file offsets

To aid in debugging, consistently print the vlentry database "address"
and the file offset when displaying errors for vlentries.  Print the
vlentry file offsets when printing all the entries with the -entries
option.

Change-Id: I3ef37e6654280f0cff9b2449da29aebe7c5e3aad
Reviewed-on: http://gerrit.openafs.org/9906
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>