LU-6772 tests: fix malform open in sanity:33d

LU-6772 tests: fix malform open in sanity:33d

The malform open original intends to verify whether panic.
Though we send a malform open flags, but it has possible
to success. So we should ignore the return value as test_33c.

Signed-off-by: Yang Sheng <yang.sheng@intel.com>
Change-Id: Ibc20e4864068f07dac30739792dc09e3844b7579
Reviewed-on: http://review.whamcloud.com/16315
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>