Easiser to switch to the requests package than to figure out how to deal
with some of the encoding changes manually. And as a bonus, it's much
nicer to work with the requests package for the future.
The queue used for varnish purges has so few entries that it's really
not worth paying the management overhead for skytools/pgq. Instead we
can use a very simple local deamon using LISTEN/NOTIFY to fire them off.
Now include a proper nagios plugin in this package, so we can get rid
of the not-very-nice munin plugin currently used in the deployment.
