Documentation/process/howto: Remove outdated info about bugzilla mailing lists

The mailing list archives[1,2] show no activity since September 2011.

[1]: https://lists.linuxfoundation.org/pipermail/bugme-new/
[2]: https://lists.linuxfoundation.org/pipermail/bugme-janitors/



Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>