src: show save message in correct language after language switch

get_std_save_message() should be removed eventually, there are only a
few callers left.  Out of lack of imagintion, just fix the apparent
issue and remove the attached filter/firewall message that doesn't
really work because it does not look for "firewall" in the script name.

(cherry picked from commit 32f2ddbc)

src/www/guiconfig.inc

@@ -261,20 +261,13 @@ function print_service_banner($service)
     }
 }
 
-function get_std_save_message()
+function get_std_save_message($raw = false)
 {
-    $filter_related = false;
-    $filter_pages = array("nat", "filter");
-    $to_return = gettext("The changes have been applied successfully.");
-    foreach($filter_pages as $fp) {
-        if (stristr($_SERVER['SCRIPT_FILENAME'], $fp)) {
-            $filter_related = true;
+    if ($raw == true) {
+        return 'The changes have been applied successfully.';
     }
-    }
-    if ($filter_related) {
-        $to_return .= "<br />" . gettext("You can also <a href=\"status_filter_reload.php\">monitor</a> the filter reload progress.");
-    }
-    return $to_return;
+
+    return gettext('The changes have been applied successfully.');
 }
 
 function get_specialnets($only_enabled=false)

src/www/system_general.php

@@ -37,7 +37,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     $pconfig = array();
 
     if (isset($_GET['savemsg'])) {
-        $savemsg = htmlspecialchars($_GET['savemsg']);
+        $savemsg = htmlspecialchars(gettext($_GET['savemsg']));
     }
 
     $pconfig['dns1gw'] = null;
@@ -229,7 +229,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         system_timezone_configure();
         filter_configure();
 
-        header(url_safe('Location: /system_general.php?savemsg=%s', array(get_std_save_message())));
+        header(url_safe('Location: /system_general.php?savemsg=%s', array(get_std_save_message(true))));
         exit;
     }
 }