This fixes the the problem that the sensor becomes unresponsive after
pressing the wrong fingerprint. We fix the problem by making sure that
the non-match report is delayed until the finger is removed. With this
we cannot run into the situation that the next match request fails
immediately as the finger is still present.
Fixes: #208
Heavily modified by Benjamin Berg <bberg@redhat.com> to port it to the
new libfprint API and adjust the coding style to follow more closely
other drivers.