Btrfs-progs: deal with mismatch index between dir index and inode ref

Btrfs-progs: deal with mismatch index between dir index and inode ref

Sometimes we have a dir index and an inode ref that don't agree on the index.
In this case just assume that the inode ref is the ultimate authority on the
subject and delete the dir index.  This means we have to not reset index if we
find a mismatched inode ref to make sure we delete the right dir index.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.cz>