fixed auth_browseruid on IE9

IE9 send different HTTP_ACCEPT_LANGUAGE header on ajax request. This causes different results from auth_browseruid. This patch removes the HTTP_ACCEPT_LANGUAGE from the browser id calculation.

_test/tests/inc/auth_browseruid.test.php

+<?php
+
+class auth_browseruid_test extends DokuWikiTest {
+
+
+    /**
+     * regression test to ensure correct browser id on IE9.
+     *
+     * IE9 send different HTTP_ACCEPT_LANGUAGE header on ajax request.
+     */
+    function testIE9JsVsDefault() {
+
+        // javascript request
+        $_SERVER['HTTP_USER_AGENT'] = 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)';
+        $_SERVER['HTTP_ACCEPT_ENCODING'] = 'gzip, deflate';
+        $_SERVER['HTTP_ACCEPT_LANGUAGE'] = 'de';
+        unset($_SERVER['HTTP_ACCEPT_CHARSET']);
+        $javascriptId = auth_browseruid();
+
+        // default request
+        $_SERVER['HTTP_USER_AGENT'] = 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)';
+        $_SERVER['HTTP_ACCEPT_ENCODING'] = 'gzip, deflate';
+        $_SERVER['HTTP_ACCEPT_LANGUAGE'] = 'de-DE';
+        $normalId = auth_browseruid();
+
+        $this->assertEquals($normalId, $javascriptId);
+
+    }
+
+}
\ No newline at end of file

inc/auth.php

@@ -311,7 +311,6 @@ function auth_browseruid() {
     $uid = '';
     $uid .= $_SERVER['HTTP_USER_AGENT'];
     $uid .= $_SERVER['HTTP_ACCEPT_ENCODING'];
-    $uid .= $_SERVER['HTTP_ACCEPT_LANGUAGE'];
     $uid .= $_SERVER['HTTP_ACCEPT_CHARSET'];
     $uid .= substr($ip, 0, strpos($ip, '.'));
     $uid = strtolower($uid);