Fix URL for horizon in Debian

This patch fixes the URL for the Horizon dashboard in
Debian. It uses https, and not /horizon (but the root
of the server).

Change-Id: If12095b61ace9c5881e4421bdca042d9b5b8449b
backport: havana
Install Guide: Fix typo

chckconfig -> chkconfig

Change-Id: I69919dd368e2c921a9ad6677cebcc2ed6b65b339
backport: havana
Merge "Fix URL for horizon in Debian"