TTY: pty, release tty in all ptmx_open fail paths

Mistakenly, commit 64ba3dc3143d (tty: never hold BTM while getting
tty_mutex) switched one fail path in ptmx_open to not free the newly
allocated tty.

Fix that by jumping to the appropriate place. And rename the labels so
that it's clear what is going on there.

Introduced-in: v2.6.36-rc2
Signed-off-by: Jiri Slaby <[e-mail]>
Cc: stable <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Alan Cox <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/pty.c

···
 
 	retval = devpts_pty_new(inode, tty->link);
 	if (retval)
-		goto out1;
+		goto err_release;
 
 	retval = ptm_driver->ops->open(tty, filp);
 	if (retval)
-		goto out2;
-out1:
+		goto err_release;
+
 	tty_unlock();
-	return retval;
-out2:
+	return 0;
+err_release:
 	tty_unlock();
 	tty_release(inode, filp);
 	return retval;