Fix manifests to work with updated puppet modules

BZ #1040021 - This patch updates the nova/neutron controller and
compute manifests to work with updated pupet modules. Specifically,
the nova auth setting should now be done via nova::api class, not
nova_config. Also, the neutron database connection should be set via
the neutron::server class, not neutron_config.

In addition, the nova compute manifest does not and should not call
the nova::api class. Instead, install the metadata-api service using
nova::generic_service.

https://bugzilla.redhat.com/show_bug.cgi?id=1040021