Fix git_number windows unit tests

This fixes python2 unit tests (py3 works fine)

Change-Id: I9b968ba5d5f534166ce6c4fe59c8dfa4beb73021
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2121563
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>

PRESUBMIT.py

@@ -80,7 +80,6 @@ def CommonChecks(input_api, output_api, tests_to_black_list, run_on_python3):
         r'.*git_common_test\.py$',
         r'.*git_hyper_blame_test\.py$',
         r'.*git_map_test\.py$',
-        r'.*git_number_test\.py$',
         r'.*git_rebase_update_test\.py$',
         r'.*ninjalog_uploader_test\.py$',
         r'.*recipes_test\.py$',

git_number.py

@@ -142,7 +142,7 @@ def finalize(targets):
 
   idx = os.path.join(git.run('rev-parse', '--git-dir'), 'number.idx')
   env = os.environ.copy()
-  env['GIT_INDEX_FILE'] = idx
+  env['GIT_INDEX_FILE'] = str(idx)
 
   progress_message = 'Finalizing: (%%(count)d/%d)' % len(DIRTY_TREES)
   with git.ProgressPrinter(progress_message) as inc: