python/qrcode: Add mock to checkInputs
python/qrcode: Add mock to checkInputs

Another test issue surfacing from the setuptools bump in
70c189976809dfdcedee4a9a69558866c1ff95a1.

This time, the tests just fail because mock is missing as a dependency.

Tested building against Python 2.7 and Python 3.6.

Signed-off-by: aszlig <ee1aa092358634f9c53f01b5a783726c9e21b35a@nix.build>
Cc: b93241f3eedf942400224177be7285565a6633c6@Mic92

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