Change value of SECRET_KEY

Currently SECRET_KEY points to
{ install_lib_dir }}/openstack_dashboard/local/.secret_key_store
however this directory is not writable by www-data:www-data and
attempting to load horizon results in a LockFailed exception being
raised.  Rather than making
{ install_lib_dir }}/openstack_dashboard/local/ writable by
www-data:www-data, we create /var/lib/horizon and point SECRET_KEY to
/var/lib/horizon/.secret_key_stone.
Revert "Default swift-proxy group for haproxy purposes"
Merge pull request #377 from rcbops/revert-376-haproxy_swift

Revert "Default swift-proxy group for haproxy purposes"
Merge pull request #366 from mattt416/issue_362

Change value of SECRET_KEY
Added missing comma which caused Kibana dashboard to not load
Merge pull request #389 from jameswthorne/master

Added missing comma which caused Kibana dashboard to not load