LU-2602 tests: add missing bug number to error_ignore call

error_ignore called with the wrong number of arguments
led to a corrupted and hard to interpret test log

Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: I6d2150eaa3c1b8cf044ddafd40d66cd64bb25314
Reviewed-on: http://review.whamcloud.com/4995
Tested-by: Hudson
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Minh Diep <minh.diep@intel.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>