ZP-860 Show Z-Push version in autodiscover.

Released under the Affero GNU General Public License (AGPL) version 3.

src/autodiscover/autodiscover.php

@@ -60,6 +60,7 @@ class ZPushAutodiscover {
      */
     public static function DoZPushAutodiscover() {
         ZLog::Write(LOGLEVEL_DEBUG, '-------- Start ZPushAutodiscover');
+        ZLog::Write(LOGLEVEL_INFO, sprintf("Z-Push version='%s'", @constant('ZPUSH_VERSION')));
         // TODO use filterevilinput?
         if (stripos($_SERVER["REQUEST_METHOD"], "GET") !== false) {
             ZLog::Write(LOGLEVEL_WARN, "GET request for autodiscover. Exiting.");