librbd: localize snap_remove op for mirror snapshots

librbd: localize snap_remove op for mirror snapshots

A client may attempt a lock request not quickly enough to
obtain exclusive lock for operations when another competing
client responds quicker. This can happen when a peer site has
different performance characteristics or latency. Instead of
relying on this unpredictable behavior, localize operation to
primary cluster.

Fixes: https://tracker.ceph.com/issues/59393
Signed-off-by: Christopher Hoffman <choffman@redhat.com>
(cherry picked from commit ac552c9b4d65198db8038d397a3060d5a030917d)

Conflicts:
	src/cls/rbd/cls_rbd.cc [ commit 3a93b40721a1 ("librbd:
	  s/boost::variant/std::variant/") not in quincy ]
	src/librbd/mirror/snapshot/UnlinkPeerRequest.cc [ ditto ]