Update salt config for apiserver to support Azure.

Shall I add the grain `cloud: gce` to the default salt scripts, and change around the `if grains['cloud'] != 'azure'` to `if grains['cloud'] == 'gce'`? Or leave as is?
grains['fqdn'] appears to be unreliable, as it depends on what is being set into the /etc/hosts file:

https://groups.google.com/forum/#!topic/salt-users/5-4i_HDmhQM

So I think this approach is ok.