LU-2194 test: remove test_19b from except list

LU-2194 test: remove test_19b from except list

the patch to fix the problem has been landed, test_19b in
recovery_small should be removed from except list.

Change-Id: I748a7dfb4f70a42a0f17ab93803cb2d6d05b32db
Signed-off-by: Hongchao Zhang <hongchao.zhang@intel.com>
Reviewed-on: http://review.whamcloud.com/13671
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>