Fix kill-script search string to match any "/libpod-"
Fix kill-script search string to match any "/libpod-"

In order to find the container hash, the "/proc/$PID/cgroup" file will
return several lines, some of them with the patterns:
  .*/libpod-<container_ID>.scope
  .*/libpod-conmon-<container_ID>.scope

The search pattern should look for "/libpod-" and the rest of the
expression will extract the container ID. That will prevent the
issue reported in the related bug, when the "pids:..." line does
not contain this information.

Change-Id: I0c017d022fbad9a8f99e5f27a7245f84de483950
Closes-Bug: #1990990

openstack/tripleo-heat-templates,openstack/tripleo-heat-templates