Log Message:
Update ruby-unicorn to 5.2.0.

* relocate website to https://bogomips.org/unicorn/
* Add some tolerance (RFC2616 sec. 19.3)
* doc: update gmane URLs to point to our own archives
* examples/logrotate.conf: update example for systemd
* doc: systemd should only kill master in example
* examples/init.sh: update to reduce upgrade racinessjr/init