Get puppet-openstack-cloud and puppetlabs-cororsync from public repo

Currently, in order to get puppet-openstack-cloud and puppetlabs-corosync
git relies on one's private key to retrieve them, since both projects are
on public repo, let's rely on git:// instead of git@
Merge pull request #441 from enovance/public_openstack_cloud

Get puppet-openstack-cloud and puppetlabs-cororsync from public repo