gluon-autoupdater: Always allow forced autoupdate.

On nodes with autoupdate disabled the cmdline parameter '-f' has no
effect. But using the autoupdater for manual updates is quite handy.
Merge pull request #23 from sargon/autoupdate-enforce

gluon-autoupdater: Always allow forced autoupdate.
Merge pull request #1 from freifunk-gluon/master

Merge upstream gluon package updates