Forwarding host should be anyOf not oneOf

Should fix #1354

backend/schema/endpoints/streams.json

@@ -21,7 +21,7 @@
       "maximum": 65535
     },
     "forwarding_host": {
-      "oneOf": [
+      "anyOf": [
         {
           "$ref": "../definitions.json#/definitions/domain_name"
         },