Revert "(experimental) force to use custom dns"

This reverts commit 2a6a5e62d4.

lib/dns/hash.py

@@ -1,37 +0,0 @@
-# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
-
-# Copyright (C) 2011 Nominum, Inc.
-#
-# Permission to use, copy, modify, and distribute this software and its
-# documentation for any purpose with or without fee is hereby granted,
-# provided that the above copyright notice and this permission notice
-# appear in all copies.
-#
-# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
-# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
-# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
-# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-
-"""Hashing backwards compatibility wrapper"""
-
-import hashlib
-import warnings
-
-warnings.warn(
-    "dns.hash module will be removed in future versions. Please use hashlib instead.",
-    DeprecationWarning)
-
-hashes = {}
-hashes['MD5'] = hashlib.md5
-hashes['SHA1'] = hashlib.sha1
-hashes['SHA224'] = hashlib.sha224
-hashes['SHA256'] = hashlib.sha256
-hashes['SHA384'] = hashlib.sha384
-hashes['SHA512'] = hashlib.sha512
-
-
-def get(algorithm):
-    return hashes[algorithm.upper()]