LU-3553 tests: volatile file test fails interop testing

LU-3553 tests: volatile file test fails interop testing

There is no volatile file support in servers before v2.3.60.
Add a version check and skip sanity test 185 entirely on old servers
to allow interop testing of 2.4+ clients on 2.3 servers.

Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: If6aef3a782307b5fe659ffcb8a8f8182f83354bd
Reviewed-on: http://review.whamcloud.com/6887
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>