In 180-increase-arp-caches the same logic was called again
and again. This could be done by a function!

See https://git.c3pb.de/freifunk-pb/ffpb-packages/issues/2

gets changed. Therefore these scripts must be adjusted
to the new structure.

See: http://gluon.readthedocs.org/en/latest/dev/upgrade.html

packages.

The file zz~-ffpb-upgrade will only be delete if its return value is 0.
For some reason we forgot to add an 'exit 0' at the end of the file if
everything is OK. This has been added.

To deal with invariant scripts that were not executed properly, we now
test the return value of do_component for these scripts as well. The
function do_component however may return early with a return code not
equal to 0, if a version for that package/script could not have been
determined. We now return the code 255 in this case and ignore that
state in "main", as we are not interested in non-ffpb packages.

Closes issue #2 by adding appropriate tests to the script as requested
by @hej, such that values that have already been set to a higher value
to not get changed.

As its name states, this packages applies some config optimizations
(like tweaking kernal knobs via sysctl) on the nodes.
For the most knobs Gluon sticks for OpenWRT defaults for good reasons,
as some values need to be set according to the environment of the
nodes (e.g. the network's size). As OpenWRT basically aims at provid-
ing a stable system for standalone WiFi access-points, the system's
default configuration may not be appropriate anymore the larger the
network grows, though.