LU-8547 test: Skip ost-pools test_24 for older MDS version

LU-8547 test: Skip ost-pools test_24 for older MDS version

Skipping ost-pools test_24 if server version is less than 2.8.56

Test-Parameters: trivial testlist=ost-pools,ost-pools,ost-pools,ost-pools
Signed-off-by: Saurabh Tandan <saurabh.tandan@intel.com>
Change-Id: Id93490606c50a0528d4576f64c808e11255ff01d
Reviewed-on: http://review.whamcloud.com/22533
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>