bug#54398: Adding network-manager-openvpn requires a full reboot

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hello Guix,

I've been bitten by this before, and again this morning, so I'm
reporting this behavior as a bug.

The struggle looks a bit like this:

1. Add the 'network-manager-openvpn' plugin to your
'network-manager-configuration', like so:

--8<---------------cut here---------------start------------->8---
(modify-services %desktop-services
 [...]
 (network-manager-service-type config =>
 		               (network-manager-configuration
			        (inherit config)
			        (vpn-plugins (list network-manager-openvpn))))
--8<---------------cut here---------------end--------------->8---

2. 'guix system reconfigure' your system with the change

3. Try configuring/importing an OpenVPN connection; it fails because the
plugin hasn't yet been made available.

4. Restart the networking service and relogin.

5. Now it seems to be functional, but the connection fails to be
established, with a timeout error.

6. Reboot the machine.

7. Try again: it now works.

Thanks,

Maxim