LU-13640 tests: add version check to conf-sanity 125

LU-13640 tests: add version check to conf-sanity 125

In Lustre 2.12.3, the l_tunedisk utility was modified to
skip tuning devices on the MDS and MGS and conf-santity
test 125 was added to check this functionality.  Thus, this
test should be skipped for all Lustre server versions prior
to 2.12.3.

Fixes: bab0570ce3081 ("LU-12387 tests: Validate l_tunedisk max_sectors_kb tuning")
Test-Parameters: trivial
Test-Parameters: serverversion=2.10.8 serverdistro=el7.6 env=ONLY=125 testlist=conf-sanity
Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I89c2900c2430ff3e76bee297809957380404aa31
Reviewed-on: https://review.whamcloud.com/38850
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Wei Liu <sarah@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>