Add stop all OST services pre-deploy hook

* 1st try to stop specified (hook hardcode) OSt services
  gracefully with stop action
* 2nd, if there are some OSt services' related processes
  are still running, send SIGKILL for all their childs as well.

Related-bug: #1364068

Change-Id: Ida1eb0fbedbd93c2898142205a09c6ee351eeac4
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>