ceph: fix possible NULL pointer dereference

This patch fixes 'event_work' dereference before it is checked for NULL.
Signed-off-by: Mariusz Kozlowski <mk@lab.zgora.pl>
Signed-off-by: Sage Weil <sage@newdream.net>

net/ceph/osd_client.c

@@ -1602,11 +1602,11 @@ void handle_watch_notify(struct ceph_osd_client *osdc, struct ceph_msg *msg)
 	     cookie, ver, event);
 	if (event) {
 		event_work = kmalloc(sizeof(*event_work), GFP_NOIO);
-		INIT_WORK(&event_work->work, do_event_work);
 		if (!event_work) {
 			dout("ERROR: could not allocate event_work\n");
 			goto done_err;
 		}
+		INIT_WORK(&event_work->work, do_event_work);
 		event_work->event = event;
 		event_work->ver = ver;
 		event_work->notify_id = notify_id;