see also e6b9b0f1:

So it seems logexpects really got some issues

- when starting with -start, there seems to exist no synchronization for
  the following vtc steps, to the extend that a logexpect -wait may
  wait for one which has already finished and a client may run before a
  logexpect has actually started (see above commit)

- yet also with running on the log head with -d1, we got no guarantee
  that all the request have pushed their logs, so add a dirty delay