fix crash due to logging during shutdown from class based DoomState

Crash was double free in ImGui::AppendLog() during shutdown. Will have to
disable the logging callback if logging should happen at that point.

src/doompanning.cc

@@ -46,11 +46,10 @@ struct DoomState
     // So easy to get this wrong and destroy the texture by accident. Cleanup is
     // now done in check_on_dooms() before erasing the state. Enabling this code
     // still works though.
-#if 0
+#if 1
     DoomState() = default;
     ~DoomState()
     {
-        log_trace("~DoomState");
         if (texture)
             SDL_DestroyTexture(texture);
     }