ss7ops: fix warning about uninitialized variable

src/modules/ss7ops/ss7ops_mod.c

@@ -327,6 +327,7 @@ static int ki_isup_to_json(sip_msg_t *_m, int proto)
 	srjson_DeleteDoc(isup_json);
 	isup_last = NULL;
 	isup_json = NULL;
+	mtp_type = 0;
 
 	data = fetch_payload(_m, "$var(payload)", &int_len);
 	if (!data)
@@ -744,4 +745,4 @@ int mod_register(char *path, int *dlflags, void *p1, void *p2)
 {
 	sr_kemi_modules_add(sr_kemi_ss7ops_exports);
 	return 0;
-}
+}