LU-10716 tests: skip sanity 56xb for old server

LU-10716 tests: skip sanity 56xb for old server

Patch skips sanity test_56xb for servers which
do not contain LU-6051.

Signed-off-by: Elena Gryaznova <c17455@cray.com>
Cray-bug-id: LUS-2609
Test-Parameters: trivial testlist=sanity envdefinitions="ONLY=56bx"
Change-Id: I1b03f5e1c144dedef2bdd7b0c46e431d6761eb47
Reviewed-on: https://review.whamcloud.com/31416
Reviewed-by: Vladimir Saveliev <c17830@cray.com>
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>