Support customize the dashboard http/https port

We need support to customize the OpenStack dashboard http and https
listen port to avoid these ports conflict with existing web application.

Change-Id: I9a3464487e0c8eb2eed397e847a9e4a6fedd43e0
upgrade local_settings.py.erb to havana.

Change login redirect url for dashboard to /admin.
upgrade local_settings.py.erb to havana.

Change-Id: I915feb334fb2015bc7007fc93e000413df1a17c4
Closes-Bug: #1267677
Merge "upgrade local_settings.py.erb to havana."