Comment 2 for bug 1275495

This should be an easy fix, but as an alternative while a developer gets around to it, you can also use the Monitoring Plugins PPA: https://launchpad.net/~pkg-nagios-devel/+archive/ubuntu/plugins. See also: https://www.monitoring-plugins.org/

Note that this will result in installing a far newer version of the plugins so you should only do this if you're willing to invest the time to also fix any potential incompatibilities due to the major version bump. That said, my own installation on a production Icinga instance went very smoothly.