ocfs2: do not log ENOENT in unlink()

Suppress log message like this: (open_delete,8328,0):ocfs2_unlink:951
ERROR: status = -2

Orabug:17445485

Signed-off-by: Xiaowei Hu <xiaowei.hu@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>