controllers: fix killbill_helper integration after 72ab0a5d2

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
devise: display custom message when Kill Bill is down

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
ability: interpret wildcards in permissions

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
test: fix tests integration with Devise and CanCan

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
gemspec: downgrade rails to 3.2.14

Now that the Devise/CanCan integration is done, downgrade to Rails 3.x.

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>