```
security/py-{acme,certbot}: update to 0.16.0
Common:
- Update PORTVERSION and distinfo checksum (0.16.0)
py-acme:
- Revert py-requests requirement to >=2.4.1 after issue 3804 was fixed. See https://github.com/certbot/certbot/issues/3804 for further details.
Changes: https://github.com/certbot/certbot/blob/master/CHANGELOG.md#0160---2017-07-05
Approved by: koobs (maintainer, py-certbot)
Diff Revision: D11517
```