add comment about pyaes issue

lib/tests/test_bitcoin.py

@@ -113,6 +113,10 @@ class Test_bitcoin(unittest.TestCase):
         password = u"uber secret"
         wrong_password = u"not the password"
         enc = pw_encode(payload, password)
+        # FIXME: pyaes does not check that padding is consistent
+        # before removing it, wich causes this test to randomly fail.
+        # Wallets are unaffected by this, because check_password
+        # includes a test of the decoded public key.
         self.assertRaises(Exception, pw_decode, enc, wrong_password)
 
     def test_hash(self):