engine: cfgscript: don't let scr vars overwrite existing variables

we don't use them for storing settings anyway
only for reference in UI

engine/common/cfgscript.c

@@ -292,6 +292,7 @@ int CSCR_WriteGameCVars( file_t *cfg, const char *scriptfilename )
 
 static void CSCR_RegisterVariable( scrvardef_t *var, void *unused )
 {
+	if( !Cvar_FindVar( var->name ))
 		Cvar_Get( var->name, var->value, var->flags|FCVAR_TEMPORARY, var->desc );
 }