Log Message:
Update security/py-certbot and security/py-acme to 0.15.0

Added
- Plugins for performing DNS challenges for popular providers
- IPv6 support in the standalone plugin.
- A mechanism for keeping your Apache and Nginx SSL/TLS configuration
  up to date.
- --http-01-address and --tls-sni-01-address flags for controlling the
  address Certbot listens on when using the standalone plugin.
- The command certbot certificates that lists certificates managed by
  Certbot now performs additional validity checks to notify you if
  your files have become corrupted.

Changed
- Messages custom hooks print to stdout are now displayed by Certbot
  when not running in --quiet mode.
- jwk and alg fields in JWS objects have been moved into the protected
  header causing Certbot to more closely follow the latest version of
  the ACME spec.

Fixed
- Permissions on renewal configuration files are now properly
  preserved when they are updated.
- A bug causing Certbot to display strange defaults in its help output
  when using Python <= 2.7.4 has been fixed.
- Certbot now properly handles mixed case domain names found in custom
  CSRs.
- A number of poorly worded prompts and error messages.

Removed
- Support for OpenSSL 1.0.0 in certbot-auto has been removed as we now
  pin a newer version of cryptography which dropped support for this
  version.