Fix html for no-reply email setting (Bug #946880)

Fix an issue wherein HTML in a warning about the no reply
email setting is displayed as plain text.

Change-Id: I8bdf8325db93dc3a2bea4e040effdb641909e8eb
Signed-off-by: Nigel Cunningham <nigelc@catalyst-au.net>

htdocs/admin/upgrade.php

@@ -18,7 +18,7 @@ require(get_config('libroot') . 'upgrade.php');
 
 if (param_integer('finished', 0)) {
     foreach (site_warnings() as $w) {
-        $SESSION->add_error_msg($w);
+        $SESSION->add_error_msg($w, FALSE);
     }
     if ($missing = check_installed_plugins()) {
         $message = get_string('installedpluginsmissing', 'admin') . ': ';