fix breakage in o2net_send_tcp_msg()

uninitialized msghdr.  Broken in "ocfs2: don't open-code kernel_recvmsg()"
by me ;-/

Cc: stable@vger.kernel.org # 3.15+
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fs/ocfs2/cluster/tcp.c

@@ -925,7 +925,7 @@ static int o2net_send_tcp_msg(struct socket *sock, struct kvec *vec,
 			      size_t veclen, size_t total)
 {
 	int ret;
-	struct msghdr msg;
+	struct msghdr msg = {.msg_flags = 0,};
 
 	if (sock == NULL) {
 		ret = -EINVAL;