Revert unnecessary function addition

Author: lukebakken

src/rabbit_core_metrics_gc.erl

@@ -54,13 +54,9 @@ terminate(_Reason, #state{timer = TRef}) ->
 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
 
-start_timer(Interval, #state{timer = TRef0} = St) ->
-    timer:cancel(TRef0),
-    TRef1 = erlang:send_after(Interval, self(), start_gc),
-    St#state{timer = TRef1}.
-
 start_timer(#state{interval = Interval} = St) ->
-    start_timer(Interval, St).
+    TRef = erlang:send_after(Interval, self(), start_gc),
+    St#state{timer = TRef}.
 
 gc_connections() ->
     gc_process(connection_created),