change dns api listen port to 8053 which is more like the real dns port

docker/docker-compose.yml

@@ -20,7 +20,7 @@ services:
     depends_on:
       - ddns
     environment:
-      PDNS_REMOTE_HTTP_HOST: "ddns:8057"
+      PDNS_REMOTE_HTTP_HOST: "ddns:8053"
 
   redis:
     restart: unless-stopped

shared/config.go

@@ -23,7 +23,7 @@ func (c *Config) Initialize() {
 	flag.StringVar(&c.SOAFqdn, "soa_fqdn", "",
 		"The FQDN of the DNS server which is returned as a SOA record")
 
-	flag.StringVar(&c.ListenBackend, "listen-backend", ":8057",
+	flag.StringVar(&c.ListenBackend, "listen-backend", ":8053",
 		"Which socket should the backend web service use to bind itself")
 
 	flag.StringVar(&c.ListenFrontend, "listen-frontend", ":8080",