Expose nova.conf config lines to be used as hiera overrides

Included nova::config in undercloud puppet-stack-config
puppet manifest so that nova configuration parameters can
be overriden using hiera overrides.

Change-Id: I71bc5ed35cc41139481ceb51216183e6c703cf01

elements/puppet-stack-config/puppet-stack-config.pp

@@ -392,6 +392,7 @@
 include ::nova::wsgi::apache_placement
 include ::nova::cron::archive_deleted_rows
 include ::nova::cron::purge_shadow_tables
+include ::nova::config
 include ::nova::conductor
 include ::nova::scheduler
 include ::nova::scheduler::filter