Merge pull request #2 from ceph/master

Rebase from upstream
Merge pull request #3 from ceph/master

Rebase from upstream
Standardising key addition

Debian based repo’s now fetch keys in a similar manner to Redhat based
ones, and both stable and dev keys have entries in vars.
Revert URL-based key addition for Debian
Merge pull request #145 from matthewrees/separate-ceph-keys

Standardising key addition