Remove the unsupported global_distrib_addr option

It was:
- not supported in the config spec, making it unusable
- documented with the old Erlang configuration format (cfg)
- untested
- placed in the wrong section of the configuration file (top level)

big_tests/tests/mod_global_distrib_SUITE.erl

@@ -66,7 +66,6 @@ groups() ->
            %% with node 2 disabled
            test_muc_conversation_on_one_host,
            test_global_disco
-           %% TODO: Add test case fo global_distrib_addr option
           ]},
          {hosts_refresher, [],
           [test_host_refreshing]},

doc/modules/mod_global_distrib.md

@@ -302,11 +302,6 @@ Number of times message delivery will be retried in case of errors.
 
 `mod_global_distrib` extension relies on [`mod_disco`](mod_disco.md)'s option `users_can_see_hidden_services`, when provided. If it is not configured, the default value is `true`. `mod_disco` does not have to be enabled for `mod_global_distrib` to work, as this parameter is used only for processing Disco requests by Global Distribution.
 
-## Overriding remote datacenter endpoints
-
-There may be cases when the endpoint list given via **endpoints** option does not accurately specify endpoints on which the node may be reached from other datacenters; e.g. in case the node is behind NAT, or in testing environment.
-The endpoints used for connection to a remote datacenter may be overridden by global option `{ {global_distrib_addr, Host}, [{IP, Port}] }`.
-
 ## Example configuration
 
 ### Configuring mod_global_distrib
@@ -326,12 +321,6 @@ The endpoints used for connection to a remote datacenter may be overridden by gl
   redis.pool = "global_distrib"
 ```
 
-### Overriding endpoints to a remote datacenter
-
-```erlang
-{ {global_distrib_addr, "datacenter2.example.com"}, [{"124.12.4.3", 5556}, {"182.172.23.55", 5555}] }.
-```
-
 ### Configuring Dynomite
 
 For more information about Dynomite configuration, consult [Dynomite wiki](https://github.com/Netflix/dynomite/wiki).

src/global_distrib/mod_global_distrib_server_mgr.erl

@@ -408,12 +408,7 @@ refresh_connections(#state{ server = Server, pending_endpoints = PendingEndpoint
 
 -spec get_endpoints(Server :: jid:lserver()) -> [mod_global_distrib_utils:endpoint()].
 get_endpoints(Server) ->
-    EndpointsToResolve =
-        %% FIXME this option does not exist
-        case mongoose_config:lookup_opt({global_distrib_addr, Server}) of
-            {error, not_found} -> mod_global_distrib_mapping:endpoints(Server);
-            {ok, Endpoints} -> Endpoints
-        end,
+    EndpointsToResolve = mod_global_distrib_mapping:endpoints(Server),
     mod_global_distrib_utils:resolve_endpoints(EndpointsToResolve).
 
 -spec resolve_pending(NewEndpointList :: [mod_global_distrib_utils:endpoint()],