support/testing: really fix python-gitdb2 test

support/testing: really fix python-gitdb2 test

The test-case for python-gitdb2 consists solely in verifying that the
module can indeed be imported.

However, flake8 errors out on unused imports. Furthermore, it also
errors about wildcard imports, as it can detect unused symbols.

Commit d8c86be9cd7 (support/testing: fix python-gitdb2 test) tried to
address this issue, by explicitly squelching the two errors, F401 and
F403.

While that works on recent distros, the image used by our docker
pipeline is laggign behind and the flake8 there only handles at most a
single error in the noqa list.

Do as is done with the other python samples, and just blindly ignore
all errors.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>