In patch 'ext4: refactor ext4_move_extents code base',  Dmitry Monakhov has
refactored ext4_move_extents' implementation, but forgot to update the
corresponding comments, this patch will try to delete some useless comments.
Reviewed-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NXiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>