LU-14838 tests: skip sanityn/32a if no truncate_lock

LU-14838 tests: skip sanityn/32a if no truncate_lock

Newer servers do not support truncate_lock since 2.14.53.
Skip sanityn.sh test_32a if this feature is not available.

Test-Parameters: trivial testlist=sanityn env=ONLY=32a
Test-Parameters: clientversion=2.14 testlist=sanityn env=ONLY=32a
Fixes: 6335dba839 ("LU-14838 osc: Remove lockless truncate")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: Ibe37b59eff2b11a1b5e6ddd7a5c0ba6dae9993f5
Reviewed-on: https://review.whamcloud.com/47554
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Sarah Liu <sarah@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>