Allow CIDR instead of iterface name

This patch implements translation from CIDR to interface name,
which should allow deployments to heretogenous infrastructure.

Package openstack-packstack-puppet will need new require,
which is rubygem-ippaddress.

Workaround for rhbz#1200604

Change-Id: Id27881f616781e5a24a1bdb1e169915b7619eebd

packstack/puppet/templates/nova_compute_flat.pp

@@ -0,0 +1,6 @@
+
+$nova_compute_privif = hiera('CONFIG_NOVA_COMPUTE_PRIVIF')
+
+nova_config {
+  'DEFAULT/flat_interface': value => force_interface($nova_compute_privif, $use_subnets);
+}