LU-6030 ldiskfs: cleanup ldiskfs_journal_dirty_metadata

LU-6030 ldiskfs: cleanup ldiskfs_journal_dirty_metadata

ldiskfs_journal_dirty_meatdata only exist in ext3 code.
In the ext4 ldiskfs_handle_dirty_metadata instead of it.
As we won't support ext3 any more, Cleanup its usage
from ldiskfs & osd.

Signed-off-by: Yang Sheng <yang.sheng@intel.com>
Change-Id: I7a1f65bd41fb552cb099831fc0254926ae5c2df3
Reviewed-on: http://review.whamcloud.com/13067
Tested-by: Jenkins
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>