Improve collectstatic handling

[ekohl]

There's currently a collectstatic job:

puppet-pulpcore/manifests/config.pp

Lines 23 to 30 in de3564f

	exec { 'django-admin collectstatic':
	path => ['/usr/local/bin', '/usr/bin'],
	environment => [
	'DJANGO_SETTINGS_MODULE=pulpcore.app.settings',
	"PULP_SETTINGS=${pulpcore::settings_file}",
	],
	refreshonly => true,
	}

This is refreshonly and uses the settings file, but doesn't refresh on it. There may also be other reasons to explicitly trigger it. For example when a yum update happens outside of its control.