Fixing errors in rgw playbook for Trusty

- We don’t need ceph-extra for trusty
- Enable multiverse repo for access to libapache2-mod-fastcgi
- Update cache before attempting to install packages to register
multiverse repo and only refresh cache once an hour to avoid delays in
the playbook
- Add wildcard to disabling default site as on Ubuntu it is 000_default
by…default
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.
Fix wrong variable for cephx signature

Add a comment for KRBD, enabling cephx signatures will prevent you to
map RBD devices.

Signed-off-by: Sébastien Han <sebastien.han@enovance.com>
Merge pull request #146 from leseb/fix-cephx

Fix wrong variable for cephx signature
Revert URL-based key addition for Debian
Merge pull request #145 from matthewrees/separate-ceph-keys

Standardising key addition
Merge pull request #142 from matthewrees/trusty-radosgw

Fixing errors in rgw playbook for Trusty
Merge pull request #6 from ceph/master

Rebase from upstream