Add support for auth_admin_prefix in glance

Add support for auth_admin_prefix in glance::registry, glance::api & in
the glance provider.

Change-Id: I646c621f0a42cd987bc409b17066f8ac13556883
Check if auth_admin_prefix is defined

Check if auth_admin_prefix is defined (passed as a parameter to api.pp)
before trying to access it in the settings data structure.

Change-Id: I61a3ae41dca2a5e5bd9e635b0a2ab9eb05b0326a
Fixes: bug #1190481
Fix misnamed protocol param in glance-api.conf

 * keystone_authtoken/protocol => auth_protocol

Change-Id: I47ba3eb584255e666f787b53d4668b74a575982f
fix api.pp and registry.pp to work with postgresql

Validation SQL connection string for postgres was wrong. Compare with
the code section som lines below the patched line, where the correct value is used.

Change-Id: I772761168374fbe4957886026b52ff607002f7d5
Merge branch 'dev' of https://github.com/gwdg/puppetlabs-glance into dev