Remove dnf from pyupdatesd

DNF is still in its infancy, and among other problems I saw, running
`dnf check-update` as a normal user returns no results and exits with
code 0, but when run with sudo will return results and exit with code
100 (the expected behavior). This script can't run sudo every time it
wants to check-update.
Merge branch 'master' of github.com:kirsle/bin