gate: drop nobarrier usage
gate: drop nobarrier usage

nobarrier has been removed from xfs and it has been deprecated
for quite sometime[0].

[0]: https://patchwork.kernel.org/patch/10487561/

Change-Id: Ia910f39b000c34f905a8184cbffa4dc3bdfed8cc

openstack/openstack-ansible,stackforge/os-ansible-deployment,openstack/openstack-ansible,stackforge/os-ansible-deployment