Arguably, CC0 is just fine for examples since they are not code. But it's
easier to be consistent and just use MIT-0 for all "documentation". Thus,
the license is changed similarly code examples under man/.
Based on 'git shortlog -ns network/*' and 'git log -p', the following folks
should ack this:
Zbigniew Jędrzejewski-Szmek
Lennart Poettering
Tom Gundersen
Yu Watanabe
Daan De Meyer
Marc-André Lureau
The file has instructions how to "enable" it by symlinking into the
appropriate place. If we create a different mechanism to do enablement
later on, we can always adjust the instructions.
Closes#3998.