Code review comment for lp://qastaging/~sajoupa/charm-haproxy/update-charmhelpers

Tested successfully that the charm builds, deploys, and sets its nrpe-external-master primary=True:

$ bzr branch lp:~sajoupa/charm-haproxy/update-charmhelpers charm-haproxy
$ cd charm-haproxy
$ charm build
$ cd builds
$ juju deploy ./haproxy
$ juju deploy cs:nrpe
$ juju add-relation haproxy:nrpe-external-master nrpe:nrpe-external-master
$ juju run --unit haproxy/0 "relation-ids nrpe-external-master"
nrpe-external-master:2
$ juju run --unit nrpe/0 "relation-get -r nrpe-external-master:2 primary haproxy/0"
True