Replaced session variable with local variable instead, on previous Upgrade Schema fix.

core/upgrade/upgrade_schema.php

@@ -75,10 +75,10 @@
 	unset($apps);
 
 //upgrade the domains
-	$_SESSION['domain_language_code'] = $_SESSION['domain']['language']['code'];
+	$domain_language_code = $_SESSION['domain']['language']['code'];
 	require_once "core/upgrade/upgrade_domains.php";
-	$_SESSION['domain']['language']['code'] = $_SESSION['domain_language_code'];
-	unset($_SESSION['domain_language_code']);
+	$_SESSION['domain']['language']['code'] = $domain_language_code;
+	unset($domain_language_code);
 
 if ($display_results && $display_type == "html") {
 	echo "<br />\n";