The behaviour of --link-mtu has changed and we increase the values to
at least have interface MTU greater than IPv6 minimum.
We'll see later to have even greater values in ovpn_link_mtu_dict
(so that the resulting MTU is closer to what we had with 2.3)
or review the whole MTU part completely.

The presence of /lib/systemd/system/*.service files masked the fact that the
/etc/init.d/ scripts were enabled, and services were not enabled under
systemd (no symlink in /etc/systemd/system/multi-user.target.wants/).

Reverting commit 4c2284e2 partially is the
easiest way to handle the case of OS upgrade (with a switch to systemd).

https://reproducible-builds.org/

Anyway, OpenVPN >= 2.3 was already missing on Squeeze, even via backports.

debian/rules is split into reusable parts for SlapOS-based packages.

The old distutils way is not compatible with zc.recipe.egg in develop mode,
because egg_info does not provide any information about such scripts.

2.2.x branch has a patch[1] that renders tls_serial_* environment variables
in base 16, causing a ValueError exception in ovpn-server hook.

[1] https://github.com/OpenVPN/openvpn/commit/7d5e26cbb53e2700c966e6b6e815f0c824da8956

This simplify network configuration a lot, and on recent kernels, this fixes
wrong source address for extra interfaces that already have a public IP.

- new -V/--version command line option
- protocol extended to get the version of any node in the network,
  which will allow to track those running an old version of re6st

Also provides systemd units.