merge r13955 from branch 2.3 to trunk

bug 2610 fixed: make sure the $_GET['lang'] or $_GET['language'] is in the
list of available languages.



git-svn-id: http://piwigo.org/svn/trunk@13956 68402e56-0260-453c-a942-63ccdbb3a9ee

install.php

@@ -165,6 +165,11 @@ $languages = new languages('utf-8');
 if (isset($_GET['language']))
 {
   $language = strip_tags($_GET['language']);
+  
+  if (!in_array($language, array_keys($languages->fs_languages)))
+  {
+    $language = PHPWG_DEFAULT_LANGUAGE;
+  }
 }
 else
 {