LU-10924 tests: conf-sanity test_116 server version check

LU-10924 tests: conf-sanity test_116 server version check

Patch "LU-10520 mkfs: enable extents for big MDT" adds test
that check if extents are enabled with 64bit option. But
Lustre FS before this patch sets ^extents opiton. So interop
testing fails.

This patch adds version check for MDT to conf-sanity test_116.

Signed-off-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
Cray-bug-id: LUS-5812
Change-Id: Ia42597174944ec1627dfe0f6a7cf8149e674cecc
Reviewed-on: https://review.whamcloud.com/32050
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>