crypto - remove stale TODOs

We do not need to test the contaiher listing etag length before
decrypting - if it has crypto-meta it will be decrypted.  The Etag
value in a response to a ranged GET should be the Etag of the whole
object.

Change-Id: Ib713a899b5d65d979d51db36cbca809998e87847

swift/common/middleware/decrypter.py

@@ -388,9 +388,6 @@ class DecrypterContContext(BaseDecrypterContext):
     def decrypt_obj_dict(self, obj_dict, key):
         ciphertext = obj_dict['hash']
         obj_dict['hash'] = self.decrypt_value_with_meta(ciphertext, key)
-
-        # TODO - did we need to use the length to decide to decrypt?
-        # if etag and (len(etag) > constraints.ETAG_LENGTH):
         return obj_dict
 
     def process_xml_resp(self, key, resp_iter):

test/unit/common/middleware/test_decrypter.py

@@ -528,8 +528,6 @@ class TestDecrypterObjectRequests(unittest.TestCase):
         resp = req.get_response(self.decrypter)
         self.assertEqual('3456789a', resp.body)
         self.assertEqual('200 OK', resp.status)
-        # TODO - how do we validate the range body if etag is for whole? Is
-        # the test actually faking the correct Etag in response?
         self.assertEqual(plaintext_etag, resp.headers['Etag'])
         self.assertEqual('text/plain', resp.headers['Content-Type'])