Check if we are not using a vendor EAP method in EAP_IDENTITY comparison.

Bug reported by Ingo Kubbilun with a patch from Reinhard Pfau, secunet AG.

src/charon/sa/authenticators/eap_authenticator.c

@@ -251,7 +251,7 @@ static eap_payload_t* server_process_eap(private_eap_authenticator_t *this,
 		case NEED_MORE:
 			return out;
 		case SUCCESS:
-			if (type == EAP_IDENTITY)
+			if (!vendor && type == EAP_IDENTITY)
 			{
 				chunk_t data;