More careful process handling wrt. procps-ng (and psmisc)

In case you missed that, in
https://oss.clusterlabs.org/pipermail/developers/2018-May/001237.html
I've raised a call to switch away from insensitive/inconsiderate usage
of ps-like commands. Primary focus was resource-agents, but pcs
apparently also uses, e.g., `killall` command without any hesitations
globally over all processes running in the system.

Please, don't do that, you don't want to be probing and affecting processes
of unrelated users, do you? For inspiration, you can have a look at how
pacemaker is going to gain such sensitivity:
https://github.com/ClusterLabs/pacemaker/pull/1493