[Cooker] devfsd.conf lacks DELETE event handler

[Borsenkow Andrej]

Now, when /dev is restored from /lib/dev-state, devfsd.conf probably 
needs DELETE event to remove possible garbage, like

CHANGE          .*              COPY    $devpath /lib/dev-state/$devname
CREATE          .*              COPY    $devpath /lib/dev-state/$devname

add

DELETE          .*              GLOBAL  unlink /lib/dev-state/$devname

This unfortunately leaves directories behind; one possibility would be 
to prune empty directories on startup?

-andrej