Fixes puppet-dashboard-worker for Ubuntu 14.04.

Here comes another small improvement that enables to run puppet-dashboard-worker with Ubuntu 14.04:

 - ensure script/delayed_worker has permission 0755
 - modified init-script puppet-dashboard-workers to wait two
   seconds in start_puppet_dashboard_workers() before
   check_puppet_dashboard_worker_status() looks for .pid-files
 - it fixes the return status when starting puppet-dashboard-worker
   in Ubuntu 14.04

It should not break any other Debian-based distribution.