mqueue: fix mq_open() file descriptor leak on user-space processes

We leak fd on lookup_one_len() failure
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

ipc/mqueue.c

@@ -705,7 +705,7 @@ SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
 	dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
 	if (IS_ERR(dentry)) {
 		error = PTR_ERR(dentry);
-		goto out_err;
+		goto out_putfd;
 	}
 	mntget(ipc_ns->mq_mnt);
 
@@ -742,7 +742,6 @@ out:
 	mntput(ipc_ns->mq_mnt);
 out_putfd:
 	put_unused_fd(fd);
-out_err:
 	fd = error;
 out_upsem:
 	mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);