add a hack that supresses a strange error (this._remote.status.data is null, even though it was downloaded correctly)

services/sync/modules/engines.js

@@ -314,7 +314,9 @@ SyncEngine.prototype = {
     this._snapshot.load();
 
     try {
+      this._remote.status.data; // FIXME - otherwise we get an error...
       yield this._remote.openSession(self.cb, this._snapshot);
+
     } catch (e if e.status == 404) {
       yield this._initialUpload.async(this, self.cb);
       return;