In xrep_findroot_block, if we find a candidate root block with sibling
pointers or sibling blocks on the same tree level, we should not return
that block as a tree root because root blocks cannot have siblings.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>