requirements: remove ordereddict

OrderedDict is included in python3 collections module.

Change-Id: I63c91e22a8f03a5e2598a224f0b1018c2951d67b

requirements.txt

@@ -8,7 +8,6 @@ Paste
 WebOb>=1.2.3
 paramiko>=1.8.0,<2.0.0
 GitPython>=0.3.3,<2.1.2
-ordereddict
 python-daemon>=2.0.4,<2.1.0
 extras
 statsd>=1.0.0,<3.0

zuul/lib/clonemapper.py

@@ -14,7 +14,7 @@
 # under the License.
 
 from collections import defaultdict
-import extras
+from collections import OrderedDict
 import logging
 import os
 import re
@@ -22,10 +22,6 @@ import re
 import six
 
 
-OrderedDict = extras.try_imports(['collections.OrderedDict',
-                                  'ordereddict.OrderedDict'])
-
-
 class CloneMapper(object):
     log = logging.getLogger("zuul.CloneMapper")
 

zuul/model.py

@@ -13,19 +13,16 @@
 # under the License.
 
 import abc
+from collections import OrderedDict
 import copy
 import logging
 import os
 import struct
 import time
 from uuid import uuid4
-import extras
 
 import six
 
-OrderedDict = extras.try_imports(['collections.OrderedDict',
-                                  'ordereddict.OrderedDict'])
-
 
 MERGER_MERGE = 1          # "git merge"
 MERGER_MERGE_RESOLVE = 2  # "git merge -s resolve"