Merge pull request #588 in ZP/z-push from bugfix/ZP-1277-fatal-error-in-ping to develop

* commit 'f6a273b2':
  ZP-1277 Try to get folder class only for non fake changes.

src/lib/request/ping.php

@@ -226,8 +226,10 @@ class Ping extends RequestProcessor {
                         self::$encoder->content($folderid);
                         self::$encoder->endTag();
                         if ($announceAggregated === false) {
+                            if (empty($fakechanges)) {
                                 self::$topCollector->AnnounceInformation(sprintf("Found change in %s", $sc->GetCollection($folderid)->GetContentClass()), true);
                             }
+                        }
                         else {
                             $announceAggregated += $changecount;
                         }