Revert "Drop py2 support in gerrit and git related files"

This reverts commit b5c7f4b46c3309d46e1796bce7fa83388af9bfd8.

Reason for revert: missing a replace for urlparse.urlparse

Original change's description:
> Drop py2 support in gerrit and git related files
>
> python3 is the only supported version of python in depot_tools.
>
> Bug: 1475402
> Change-Id: Ie4ee18d297081b3aa0206b8d7ce6461819bff0ca
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4809560
> Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>
> Commit-Queue: Gavin Mak <gavinmak@google.com>

Bug: 1475402
Change-Id: Idd00fdfe0b3d62785da2789a7dfcc9fbc79b6385
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4811623
Reviewed-by: Aravind Vasudevan <aravindvasudev@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>
diff --git a/git_cl.py b/git_cl.py
index 352bf8a..b0f7efb 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -7,6 +7,8 @@
 
 """A git-command for integrating reviews on Gerrit."""
 
+from __future__ import print_function
+
 import base64
 import collections
 import datetime
@@ -53,9 +55,14 @@
 import swift_format
 import watchlists
 
+from third_party import six
 from six.moves import urllib
 
 
+if sys.version_info.major == 3:
+  basestring = (str,)  # pylint: disable=redefined-builtin
+
+
 __version__ = '2.0'
 
 # Traces for git push will be stored in a traces directory inside the
@@ -915,7 +922,7 @@
 
   if isinstance(arg, int):
     return _ParsedIssueNumberArgument(issue=arg)
-  if not isinstance(arg, str):
+  if not isinstance(arg, basestring):
     return fail_result
 
   if arg.isdigit():
@@ -3172,7 +3179,7 @@
     return '\n'.join(self._description_lines)
 
   def set_description(self, desc):
-    if isinstance(desc, str):
+    if isinstance(desc, basestring):
       lines = desc.splitlines()
     else:
       lines = [line.rstrip() for line in desc]