Fix 'request_handlers' transformation

Fixes #2925

src/ejabberd_config_transformer.erl

@@ -267,7 +267,7 @@ replace_request_handlers(Opts) ->
 		     (PathMod) ->
 			  PathMod
 		  end, Handlers1),
-    lists:filtermap(
+    Opts1 = lists:filtermap(
 	      fun({captcha, _}) -> false;
 		 ({register, _}) -> false;
 		 ({web_admin, _}) -> false;
@@ -280,9 +280,13 @@ replace_request_handlers(Opts) ->
 				   [adjust_hint()]),
 		      false;
 		 ({request_handlers, _}) ->
-	      {true, {request_handlers, Handlers2}};
+		      false;
 		 (_) -> true
-      end, Opts).
+	      end, Opts),
+    case Handlers2 of
+	[] -> Opts1;
+	_ -> [{request_handlers, Handlers2}|Opts1]
+    end.
 
 remove_xmlrpc_access_commands(Opts) ->
     lists:filter(