Release all IP in shorewal dynamic

[stephdl]

With the move ipset for fail2ban, it possibly have some IP still banned in the dynamic zone of shorewall, we can release them safely, when fail2ban will restart, the logs will be inspected again and the relevant IP will be banned in ipset

NethServer/dev#5943

[nethbot]

in 7.7.1908/autobuild:

• nethserver-fail2ban-1.2.1-1.34.pr76.g6a947a6.ns7.noarch.rpm x86_64 armhfp aarch64

[gsanchietti]

The action should be called once after the upgrade.
This implementation wipes the dynamic chain at every fail2ban update preventing the use of shorewall block command.

[gsanchietti]

The /var/lib/nethserver/fail2ban/fail2ban.json file could be used as a flag: if it contains the IPList (or IPDebug) field, we are doing an upgrade.
The field will be removed on next fail2ban-statistics run: https://github.com/NethServer/nethserver-fail2ban/blob/master/root/usr/libexec/nethserver/fail2ban-statistics#L79

[nethbot]

in 7.7.1908/autobuild:

• nethserver-fail2ban-1.2.1-1.34.pr76.g956ef61.ns7.noarch.rpm x86_64 armhfp aarch64

[gsanchietti]

I'd use grep instead of bash matching operator, but it's ok :)