fix warnings

src/redirect.php

@@ -165,9 +165,11 @@ if ($javascript_setting != SMPREF_JS_ON){
 setPref($data_dir, $username, 'javascript_on', $js_pref);
 
 /* Compute the URL to forward the user to. */
-    $session_expired_location= $_SESSION['session_expired_location'];
-    $session_expired_post= $_SESSION['session_expired_post'];
-
+    if (isset($_SESSION['session_expired_location']) {
+	$session_expired_location= $_SESSION['session_expired_location'];
+    } else {
+	$session_expired_location=false;
+    }
     if (isset($session_expired_location) && $session_expired_location) {
        $compose_new_win = getPref($data_dir, $username, 'compose_new_win', 0);
        if ($compose_new_win) {
@@ -177,8 +179,6 @@ setPref($data_dir, $username, 'javascript_on', $js_pref);
        }
        sqsession_unregister('session_expired_location');
        unset($session_expired_location);
-
-
     } else {
        $redirect_url = 'webmail.php';
     }