LU-2547 test: re-enable 24a/b of recovery-small

LU-2547 test: re-enable 24a/b of recovery-small

Re-enable test_24a/b of recovery-small.

Test-Parameters: trivial testlist=recovery-small,recovery-small,recovery-small
Test-Parameters: testlist=recovery-small,recovery-small,recovery-small

Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Change-Id: Ie3d111e36a5a3792b3c3b5a7bd7f6b9979a321d5
Reviewed-on: http://review.whamcloud.com/22020
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>