Code review comment for lp:~benji/charms/precise/juju-gui/fix-cache-headers

This branch looks good Benji, thank you!
I am doing QA now.
Please take a look at the comment below.

113 + if is_legacy_juju:
114 + hostname = unit_info['public-address']
115 + self.addCleanup(
116 + self.stop_services,
117 + hostname, ['haproxy', 'apache2', 'juju-api-agent'])

It's nice to have this logic abstracted in its own method.
However, while this is correct for test_api_agent, test_cache_headers
and test_branch_source, for test_staging we need to replace
'juju-api-agent' with 'juju-api-improv' in the list of services:

146 - hostname, ['haproxy', 'apache2', 'juju-api-improv'])