Only save MP match settings if the player is the controller

Broken in 72f0fdb41b.

Differential Revision: https://code.wildfiregames.com/D4112
This was SVN commit r25732.

binaries/data/mods/public/gui/gamesetup/Controllers/GameSettingsController.js

@@ -296,6 +296,7 @@ class GameSettingsController
 
 	savePersistentMatchSettings()
 	{
+		if (g_IsController)
 			// TODO: ought to only save a subset of settings.
 			this.persistentMatchSettings.saveFile(this.getSettings());
 	}