kill -SIGINT <perfspect pid> is not cleanly exiting during 'metrics' command

[harp-intel]

Ctrl-C in the terminal works because it sends SIGINT to the perfspect process and all children. 'kill' is sending SIGINT only to the perfspect process. Using the trick of negating the parent process pid in the kill command to send SIGINT to all processes in the process group doesn't work when the perfspect process is disconnected from its parent with the 'disown' command as is necessary when run through some scripting tools, e.g., ansible.

Potential solution is for the perfspect process to catch the SIGINT signal and re-send to its children.