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

This reverts commit b5c7f4b46c.

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>

git_mark_merge_base.py

@@ -11,6 +11,8 @@ purposes of the chromium depot_tools git extensions. Passing no arguments will
 just print the effective merge base for the current branch.
 """
 
+from __future__ import print_function
+
 import argparse
 import sys