deprecate sha1/md5_constructor from koji.util

These functions are now fully provided by hashlib. Commit removes their
usage from koji's codebase and leaves deprecation message in lib.

Final removal from lib is scheduled to 1.21.

Fixes: https://pagure.io/koji/issue/1487

cli/koji_cli/commands.py

@@ -2,9 +2,9 @@ from __future__ import absolute_import
 from __future__ import division
 
 import ast
-import base64
 from collections import defaultdict, OrderedDict
 import fnmatch
+import hashlib
 import json
 import logging
 import os
@@ -35,7 +35,7 @@ except ImportError:  # pragma: no cover
         yumcomps = None
 
 import koji
-from koji.util import md5_constructor, to_list, base64encode
+from koji.util import to_list, base64encode
 from koji_cli.lib import _, activate_session, parse_arches, \
         _unique_path, _running_in_bg, _progress_callback, watch_tasks, \
         arg_filter, linked_upload, list_task_output_all_volumes, \
@@ -1481,7 +1481,7 @@ def handle_import_sig(goptions, session, args):
         previous = session.queryRPMSigs(rpm_id=rinfo['id'], sigkey=sigkey)
         assert len(previous) <= 1
         if previous:
-            sighash = md5_constructor(sighdr).hexdigest()
+            sighash = hashlib.md5(sighdr).hexdigest()
             if previous[0]['sighash'] == sighash:
                 print(_("Signature already imported: %s") % path)
                 continue