horizon master branch (for Queens) dropped run_tests.sh in favor of tox.
compilemessages needs to be run in a different way.
Also improves some logics:
* Cleanup stale compiled python files
* DJANGO_SETTINGS_MODULE=openstack_dashboard.settings is no longer needed
as this is the default value of manage.py in the horizon repo
Change-Id: If823e8e63c251dab0d764212eba2ec77774f789e
The translation check site is not available yet. It looks better to
improve the way to check Horizon translation using DevStack environment.
This commit also adds how to import latest translations
when DevStack is running.
Change-Id: I61b06aa09a62893d56b66ad9820f3d8cc958ac23