Use the copy of the release GPG key in puppet
Fix Ubuntu repository handling

Install the GPG release key C1240596 in GnuPG keyring format
from puppet instead of keyserver.

euca2ools 3.1 is not available as as .deb package from
downloads.eucalyptus.com. Ubuntu ships euca2ools 2.1.1 (raring),
2.1.3 (saycy), 3.0.2 (trusty).

Fail if the operating system is not supported and make puppet-lint
happy by having a default case in switch statement.
Merge pull request #2 from pabl0/repo

repo.pp improvements
[ merged -- thanks pabl0! ]