support/testing: fix python-gitdb2 test

Cthe 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.

Squelch those errors.

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

support/testing/tests/package/sample_python_gitdb2.py

@@ -1 +1 @@
-from gitdb import *
+from gitdb import *  # NOQA: F401 F403