Configure endpoints to use SSL natively or via proxy

Configure nova, cinder, glance, swift and neutron to use SSL
on the endpoints using either SSL natively or via a TLS proxy
using stud.

To enable SSL via proxy, in local.conf add

ENABLED_SERVICES+=,tls-proxy

This will create a new test root CA, a subordinate CA and an SSL
server cert. It uses the value of hostname -f for the certificate
subject. The CA certicates are also added to the system CA bundle.

To enable SSL natively, in local.conf add:

USE_SSL=True

Native SSL by default will also use the devstack-generate root and
subordinate CA.

You can override this on a per-service basis by setting

<SERVICE>_SSL_CERT=/path/to/cert
<SERVICE>_SSL_KEY=/path/to/key
<SERVICE>_SSL_PATH=/path/to/ca

You should also set SERVICE_HOST to the FQDN of the host. This
value defaults to the host IP address.

Change-Id: I36fe56c063ca921131ad98439bd452cb135916ac
Closes-Bug: 1328226
Merge branch 'master' of https://github.com/openstack-dev/devstack