squid: mds/quiesce: overdrive an export if it hasn't frozen the tree yet

squid: mds/quiesce: overdrive an export if it hasn't frozen the tree yet

Just like with the fragmenting, we should abort an ongoing export
if a quiesce is attempted for the directory.

To minimize the stress for the system, we only allow the abort
if the export hasn't yet managed to freeze the tree. If that is the case,
then quiesce will have to wait for the export to finish.

Fixes: https://tracker.ceph.com/issues/66123
Signed-off-by: Leonid Usov <leonid.usov@ibm.com>
(cherry picked from commit da5c263b8e7797eac6c9d13d5b6a6b292d9c5def)
Fixes: https://tracker.ceph.com/issues/66259