net/tcp_ao: Don't leak ao_info on error-path

It seems I introduced it together with TCP_AO_CMDF_AO_REQUIRED, on
version 5 [1] of TCP-AO patches. Quite frustrative that having all these
selftests that I've written, running kmemtest & kcov was always in todo.

[1]: https://lore.kernel.org/netdev/20230215183335.800122-5-dima@arista.com/

Reported-by: Jakub Kicinski <kuba@kernel.org>
Closes: https://lore.kernel.org/netdev/20240617072451.1403e1d2@kernel.org/
Fixes: 0aadc73 ("net/tcp: Prevent TCP-MD5 with TCP-AO being set")
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240619-tcp-ao-required-leak-v1-1-6408f3c94247@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv4/tcp_ao.c

@@ -1968,8 +1968,10 @@ static int tcp_ao_info_cmd(struct sock *sk, unsigned short int family,
 		first = true;
 	}
 
-	if (cmd.ao_required && tcp_ao_required_verify(sk))
-		return -EKEYREJECTED;
+	if (cmd.ao_required && tcp_ao_required_verify(sk)) {
+		err = -EKEYREJECTED;
+		goto out;
+	}
 
 	/* For sockets in TCP_CLOSED it's possible set keys that aren't
 	 * matching the future peer (address/port/VRF/etc),