Fix rpc shutdown event condition bug

We want to wait for the cl_users to go down to zero, not for it to stay
positive. Quoth Trond (who wasn't even the author, but acked the wrong
version): "Argh! I need to increase my daily caffeine dosages."

Signed-off-by: Linus Torvalds <[e-mail]>

net/sunrpc/clnt.c

···
 		clnt->cl_dead = 0;
 		rpc_killall_tasks(clnt);
 		wait_event_timeout(destroy_wait,
-			atomic_read(&clnt->cl_users) > 0, 1*HZ);
+			!atomic_read(&clnt->cl_users), 1*HZ);
 	}
 
 	if (atomic_read(&clnt->cl_users) < 0) {