SUNRPC: Add a (empty for the moment) destructor for rpc_wait_queues

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 9bf118c..85199c6 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1052,6 +1052,11 @@
 	xprt->shutdown = 1;
 	del_timer_sync(&xprt->timer);
 
+	rpc_destroy_wait_queue(&xprt->binding);
+	rpc_destroy_wait_queue(&xprt->pending);
+	rpc_destroy_wait_queue(&xprt->sending);
+	rpc_destroy_wait_queue(&xprt->resend);
+	rpc_destroy_wait_queue(&xprt->backlog);
 	/*
 	 * Tear down transport state and free the rpc_xprt
 	 */