None of our scripts can handle fastd and tunneldigger running at the same
time. When both are installed, ignore tunneldigger.
(cherry picked from commit f6df3b0541)
The generic upgrade script is moved to run after the more specific scripts.
In addition, the script will now remove the configuration sections of
uninstalled VPN packages, so both positive and negative changes of the
default enable state can be migrated correctly.
Based-on-patch-by: Cyrus Fox <cyrus@lambdacore.de>
Fixes: #1187
