Always set ec2_* and my_ip options in nova.conf

They were only set when quantum is not used, but that makes no sense.

Also osapi_host doesn't exist anymore.
Merge pull request #179 from vuntz/set-ec2-options

Always set ec2_* and my_ip options in nova.conf
Register endpoints with public name and FQDN when possible

When using SSL, the common name field in the certificates is checked,
and using IP addresses won't work with that.

Internally to the OpenStack setup, it is always fine to use the FQDN
from the node, so we use this in the internal and admin URLs of the
endpoints.

For the public URL, we prefer to use the public name if it is set. If it
it not set, then we use the public FQDN only if SSL is enabled;
otherwise, we prefer the IP address (like before) because we're not 100%
sure that the administrator will have completed a proper DNS setup where
the public FQDN generated by Crowbar will be announced externally.
Restrict metadata service to only listen on admin IP address

This service is dedicated to instance guests, and is proxied there. It
should not be reachable from the external network.

Also, do not make it use SSL as quantum currently only supports metadata
running on http.