git-cl: Fix call to GetChange.

GetChange now takes a single argument.

Bug: 1042324, 1050198
Change-Id: Ib8521d7134e9c7b251d590dac6759a6cc585d3b4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2044971
Reviewed-by: Anthony Polito <apolito@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

git_cl.py

@@ -407,8 +407,7 @@ def _get_bucket_map(changelist, options, option_parser):
   # If no bots are listed, we try to get a set of builders and tests based
   # on GetPreferredTryMasters functions in PRESUBMIT.py files.
   if not options.bot:
-    change = changelist.GetChange(
-        changelist.GetCommonAncestorWithUpstream(), None)
+    change = changelist.GetChange(changelist.GetCommonAncestorWithUpstream())
     # Get try masters from PRESUBMIT.py files.
     masters = presubmit_support.DoGetTryMasters(
         change=change,