python-nfc: fix autobuild failures

Fixes autobuild failures such as the following.

  http://autobuild.buildroot.net/results/2e1/2e11b9e946a854deb28ba144ca7e398a9c996a02/



Signed-off-by: Simon Dawson <spdawson@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>