LU-7043 test: skip conf-sanity test_86

LU-7043 test: skip conf-sanity test_86

Skip conf-sanity test_86 if server version is older than 2.7.56

Test-Parameters: trivial testlist=conf-sanity

Change-Id: Ief0ef51afd50c3b8f7861d62e0231b1a923435e6
Signed-off-by: Wei Liu <wei3.liu@intel.com>
Reviewed-on: http://review.whamcloud.com/19176
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: James Nunez <james.a.nunez@intel.com>
Reviewed-by: Saurabh Tandan <saurabh.tandan@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>