Overwrite hostname reported by ganglia

User ganglia's overwrite_hostname to force the VM hostname. Avoids VMs
on private networks to appear as their gateway in the ganglia monitoring
interface. Requires ganglia puppet module at commit
MadMalcolm/puppet-ganglia@7e0c34f6e5397f5b49e01a832ac3741c90c13c2a.
Added group ssh keys for debugging access.

Changes:
	modified:   manifests/site.pp
	modified:   modules/gce_node/manifests/init.pp
Add type to ssh key entries

Fix ssh key insertion by adding encryption type to each puppet entry.

Changes:
	modified:   manifests/site.pp
Remove operatingsystemmajorrelease from puppet

Ensure modules work with CernVM by removing operatingsystemmajorrelease
fact. Wait for puppet and facter to be updated on CernVM.

Changes:
	modified:   modules/packagerepos/manifests/yumrepos.pp
Insert missing \ which broke one of the yum repos

Changes:
	modified:   modules/packagerepos/manifests/yumrepos.pp