Use eventGameLoaded for Cobra AI group initialization

Uses the `eventGameLoaded` event in place of `eventGameInit` (we don't need to double init groups at the start of a fresh non-saveloaded match).

data/mp/multiplay/skirmish/cobra_includes/events.js

@@ -1,7 +1,7 @@
 //This file contains generic events. Chat and research events are split into
 //their own seperate files.
 
-function eventGameInit()
+function eventGameLoaded()
 {
 	initCobraGroups();
 }