clean_stale: Stop updating DNS

See merge request !11

We are replacing the PowerDNS service with AWS Route 53. After this
change, we will no longer be able to use our existing DNS API.

We will soon be shutting down the Nova virtualization system, at which
point this code will become irrelevant. Instead of spending time
updating it to work with AWS Route 53, remove the DNS update
functionality.

The ipaddress-module expects either a unicode string or a bytes
object. This patch updates fwb-sync to convert all addresses to
unicode strings before passing them to ipaddress.

This patch fixes the following error:

> ipaddress.AddressValueError: '158.38.0.168' (len 12 != 4) is not
> permitted as an IPv4 address. Did you pass in a bytes (str in
> Python 2) instead of a unicode object?

Also regenerate iptables ruleset when library groups change

See merge request !10

When a new address is detected, both routers attempt to register it at
the same time. This leads to a race condition where both nodes attempt
to write to the same key at the same time.

There was already a fix for this in the code, but it used the wrong
exception. This patch updates the code to use the correct exception.

The new OpenBFDD package installs the binaries to `/usr/bin` instead
of `/usr/local/bin`. This patch updates the code with the new path.

This will ease testing in preperation for router upgrade.

The old pip in wheezy tries to access the repository over http by default and that is no longer available. This tricks it into using https

This gives at least 90% reduction in memory usage per ipset

This should fix one more case where the configurator process stops because of duplicate rules added

Library groups

namedrop @olav.morken

See merge request !9