Yes, the test fails for me without the patch.  With just the test diff applied on master, that test dumps core.

$ python setup.py test
...
test_rfc3211_test_vectors (tests.test_evp.PBKDF2TestCase) ... *** stack smashing detected ***: python terminated
Aborted (core dumped)

$ python tests/test_evp.py
................*** stack smashing detected ***: python terminated
Aborted (core dumped)

While pbkdf2 is usually used to derive a single 16 or 32 byte key, the pbkdf2 standard allows for arbitrary length key derivation.  (And there's no restriction in M2Crypto's wrapper that keylen be <= EVP_MAX_KEY_LENGTH so segfaults are possible.)