Remove old CernVM configuration

Remove obsolete cernvm configuration. With the release of uCernVM these
stopped being needed.

Changes:
	deleted:    cernvm/manifests/init.pp
	deleted:    cernvm/templates/site.conf.erb
Set up cvmfs differently depending on whether wpad is detected

Use different cvmfs configuration if wpad is detected. Don't rely on
shoal to rewrite the config properly

Changes:
	modified:   gce_node/manifests/atlas.pp
Configure ganglia to report datacentred VMs to GRIDPP_CLOUD

Add new GridPP cloud called datacentred to the GRIDPP_CLOUD ganglia
reporting.

Changes:
	modified:   gce_node/manifests/atlas.pp