CephFS drivers don't support cloning snapshots
into shares. Manila's tempest tests need to be
told this explicitly. So, update the gate hooks
that control tempest configuration.
This affects all legacy style CephFS jobs that
use devstack-gate. These jobs will go away soon,
and be replaced with Zuulv3 native style job
definitions and this patch is a stop-gap,
because devstack-plugin-ceph is a branchless
devstack plugin, and we need to support legacy
style jobs for a while.
Signed-off-by: Goutham Pacha Ravi <email@example.com>