Fix apache deprecation warnings

   - [sloth] warning: Dynamic lookup of $apache_no_default_site at /srv/leap/puppet/modules/apache/manifests/base.pp:46 is deprecated. For more information, see http://docs.puppetlabs.com/guides/scope_and_puppet.html. To see the change in behavior, use the --debug flag.

(from redmine: created on 2013-01-29, closed on 2013-04-18)