```
security/py-{acme,certbot}: update to 0.16.0
Common:
- Update PORTVERSION and distinfo checksum (0.16.0)
Changelog:
https://github.com/certbot/certbot/blob/master/CHANGELOG.md#0160---2017-07-05
Reviewed_by: koobs (maintainer, py-certbot)
Approved by: koobs (maintainer, py-certbot)
Differential_Revision: D11517
```