ocfs2: Remove struct ocfs2_journal_handle in favor of handle_t

This is mostly a search and replace as ocfs2_journal_handle is now no more
than a container for a handle_t pointer.

ocfs2_commit_trans() becomes very straight forward, and we remove some out
of date comments / code.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/dir.h b/fs/ocfs2/dir.h
index 5f614ec..3f67e14 100644
--- a/fs/ocfs2/dir.h
+++ b/fs/ocfs2/dir.h
@@ -45,7 +45,7 @@
 				 struct buffer_head **ret_de_bh);
 struct ocfs2_alloc_context;
 int ocfs2_do_extend_dir(struct super_block *sb,
-			struct ocfs2_journal_handle *handle,
+			handle_t *handle,
 			struct inode *dir,
 			struct buffer_head *parent_fe_bh,
 			struct ocfs2_alloc_context *data_ac,