Comment 5 for bug 1673064

I've done some further light testing, fixed a minor issue, and pushed the result to cs:~nrpe-charmers/nrpe-8; I've requested promulgation to cs:nrpe, which hopefully will happen in the next day or so. Please note that due to bugs #1629127 and #1687348, existing installations will need manual cleanup of old checks in /etc/nagios/nrpe.d/.