LU-14642 tests: skip sanity-flr/100 for old servers

LU-14642 tests: skip sanity-flr/100 for old servers

The new FLR FSX mode in sanity-flr test_100 triggers LU-13730 when
run on old servers.  Skip it in this case.

Test-Parameters: trivial testlist=sanity-flr env=ONLY=100
Test-Parameters: serverversion=2.14 testlist=sanity-flr env=ONLY=100
Fixes: 90ba8b4ac360 ("LU-14642 test: add fsx mirror file test mode")
Fixes: 571f3cf11159 ("LU-13730 lod: don't confuse stale with primary flag")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I595bba6d5ab318ae591d80704c70998af9166de1
Reviewed-on: https://review.whamcloud.com/47567
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Wei Liu <sarah@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>