libceph: assert both regular and lingering lists in __remove_osd()

commit 7c6e6fc5 upstream.

It is important that both regular and lingering requests lists are
empty when the OSD is removed.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

net/ceph/osd_client.c

@@ -1008,6 +1008,8 @@ static void __remove_osd(struct ceph_osd_client *osdc, struct ceph_osd *osd)
 {
 	dout("__remove_osd %p\n", osd);
 	BUG_ON(!list_empty(&osd->o_requests));
+	BUG_ON(!list_empty(&osd->o_linger_requests));
+
 	rb_erase(&osd->o_node, &osdc->osds);
 	list_del_init(&osd->o_osd_lru);
 	ceph_con_close(&osd->o_con);