staging/lustre/ptlrpc: fix ptlrpc_stop_pinger logic

It was introduced due to a patch hunk when porting
commit 20802057 (staging/lustre/ptlrpc: race in pinger).

Cc: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Cc: stable <stable@vger.kernel.org> # 3.12
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/ptlrpc/pinger.c

@@ -409,8 +409,8 @@ int ptlrpc_stop_pinger(void)
 	struct l_wait_info lwi = { 0 };
 	int rc = 0;
 
-	if (!thread_is_init(&pinger_thread) &&
-	    !thread_is_stopped(&pinger_thread))
+	if (thread_is_init(&pinger_thread) ||
+	    thread_is_stopped(&pinger_thread))
 		return -EALREADY;
 
 	ptlrpc_pinger_remove_timeouts();