The logic to check if the inode is already in the log can now be
simplified since we always wait for the ordered extents to complete
before deciding whether the inode needs to be logged. The big comment
about it can go away too.

CC: Filipe Manana <fdmanana@suse.com>
Suggested-by: NFilipe Manana <fdmanana@suse.com>
[ code and changelog copied from mail discussion ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>