qa: fix cephfs-mirror unwinding and 'fs volume create/rm' order

qa: fix cephfs-mirror unwinding and 'fs volume create/rm' order

* Fixes the 'fs volume create' happens before the cephfs-mirror daemon start.
* Fixes the 'fs volume rm' happen only after the cephfs-mirror daemon unwinding.
  - This prevents the issue of mirror-daemon not returning from a libcephfs call, as
    the volumes were deleted during the cephfs_mirror_thrash ing.

Fixes: https://tracker.ceph.com/issues/61182
Signed-off-by: Jos Collin <jcollin@redhat.com>
(cherry picked from commit b9a1a3cdf9770bcb27d6e08ddbc059f01674f4b8)