xfs_scrub: don't warn about confusing names if dir/file only writable by root

xfs_scrub: don't warn about confusing names if dir/file only writable by root

If we are scanning the directory entries or attribute names of a
dir/file and the inode can only be written by root, don't warn about
Unicode confusable names by default because the system administrator
presumably made the system like that.  Also don't warn about really
short confusable names because of the high chance of collisions.  If
the caller really wants all the output, they can run in verbose mode.

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