Revert "Add python3 support to bot_update recipe module"

This reverts commit edb6e8c51f.

Reason for revert: missing some py3 changes 

Original change's description:
> Add python3 support to bot_update recipe module
>
> Bug: 1227140
> Change-Id: Id4938c966da54957f84f59d0aef0c68c381ad5f6
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3016032
> Reviewed-by: Josip Sokcevic <sokcevic@google.com>
> Commit-Queue: Gavin Mak <gavinmak@google.com>

Bug: 1227140
Change-Id: If0852908b112ff6bdd4152189c7cb198eebd2c22
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3022309
Auto-Submit: Gavin Mak <gavinmak@google.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>

recipes/recipe_modules/bot_update/resources/bot_update.py

@@ -5,9 +5,9 @@
 
 # TODO(hinoka): Use logging.
 
-from __future__ import division
 from __future__ import print_function
 
+import cStringIO
 import codecs
 from contextlib import contextmanager
 import copy
@@ -18,24 +18,19 @@ import json
 import optparse
 import os
 import pprint
+import random
 import re
 import subprocess
 import sys
 import tempfile
 import threading
 import time
+import urllib2
+import urlparse
 import uuid
 
 import os.path as path
 
-# TODO(crbug.com/1227140): Clean up when py2 is no longer supported.
-try:
-  from cStringIO import StringIO
-  import urlparse
-except ImportError:  # pragma: no cover
-  from io import StringIO
-  import urllib.parse as urlparse
-
 # How many bytes at a time to read from pipes.
 BUF_SIZE = 256
 
@@ -175,7 +170,7 @@ def call(*args, **kwargs):  # pragma: no cover
   stdin_data = kwargs.pop('stdin_data', None)
   if stdin_data:
     kwargs['stdin'] = subprocess.PIPE
-  out = StringIO()
+  out = cStringIO.StringIO()
   new_env = kwargs.get('env', {})
   env = os.environ.copy()
   env.update(new_env)
@@ -460,7 +455,7 @@ def create_manifest():
         for path, info in json.load(f).items()
         if info['rev'] is not None
       }
-  except (ValueError, SubprocessFailed):
+  except ValueError, SubprocessFailed:
     return {}
   finally:
     os.remove(fname)
@@ -603,7 +598,7 @@ def _maybe_break_locks(checkout_path, tries=3):
             print('FAILED to break lock: %s: %s' % (to_break, ex))
             raise
 
-  for _ in range(tries):
+  for _ in xrange(tries):
     try:
       attempt()
       return