xfs_repair: notify user if free inodes contain errors

xfs_repair: notify user if free inodes contain errors

xfs_repair checks allocated but unused (free) inodes in on-disk clusters,
and up until now silently repairs any errors, and as a result does not
alter exit status if errors are found.

The in-kernel verifiers will be noisy about these errors and instruct
the user to run repair, so it's best if repair is explicit about any
fixes it makes.

This shamelessly re-uses xfs_dinode_verify for this purpose.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>