We can't trust ipmitool to terminate in time. We may have to kill
the process if it's running for longer than we asked it to.
On the other hand, abrupt IPMI exchange termination is said to be
dangerous to the state of the BMC being managed. Therefore this patch
only kills timed out IPMI "power status" call.
For the purpose of killing hung `ipmitool` we inject the time-capped
`popen.wait` call before the uncapped `popen.communicate` is called
internally. Then just kill stuck `ipmitool` process and go on.
Story: 2004449
Task: 28127
Change-Id: I7e1eafb334fe3a3337926aca27c14fe559ce0e39
9efb9e313d