sets novnc endpoint uri to https if tls is enabled

If novnc proxy is being served behind stunnel then the uri
sent to user needs to be an https endpoint. This patch checks if
stunnel is set and makes the relevant change

Change-Id: Ib6a498e469a8ce470c1e376b45efd8103e6f508e
Merge "sets novnc endpoint uri to https if tls is enabled"