Configure qpid_hostname for Controller host groups

The default controller common manifest assumes that qpid is
running locally on the same machine. This may or may not be the case
and therefore it should take the '$qpid_host' parameter used within
other manifests. Without this change, Nova attempts to use
localhost as it's qpid broker, which obviously breaks if using
multiple controller hosts.
Merge branch 'master' of https://github.com/rdoxenham/astapor
Adds section for memcached settings in manifests

The current manifests do not offer the user the chance to
override the default memcached settings. It always defaults
to the localhost. This change updates the manifests to allow
the user to override.

Note that we'll need to update the installer packages to set
a default override parameter.