* Output status for `revoke` operation. Fixes#2819.
- Added method to `certbot.display.ops` to output confirmation of `revoke`.
- Wrapped call to `acme.client.Client.revoke` in a try to statement to
handle possible error.
- Added test for `main.revoke`.
* Added test for failure of certificate revocation.
Moved creation of mocks into RevokeTest setup function.
Stopped mocks in RevokeTest teardown function.
* Fixed lint errors.
* Do not call `unittest.TestCase.assertRaises` as a context manager (to work with py26).
* Fixed spelling error in successful revocation notification.
Added test for the notification.