scripts: convert random standalone programs to python3 only

Nothing imports these, so should be safe to convert.

BUG=chromium:997354
TEST=CQ passes

Change-Id: Iced71210aca4ef7e83235b5d8a2959da0193646e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2071695
Reviewed-by: Alex Klein <saklein@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/sync_chrome.py b/scripts/sync_chrome.py
index 14022f7..aa50f67 100644
--- a/scripts/sync_chrome.py
+++ b/scripts/sync_chrome.py
@@ -8,6 +8,7 @@
 from __future__ import print_function
 
 import os
+import sys
 
 from chromite.lib import constants
 from chromite.lib import commandline
@@ -17,6 +18,9 @@
 from chromite.lib import osutils
 
 
+assert sys.version_info >= (3, 6), 'This module requires Python 3.6+'
+
+
 def GetParser():
   """Creates the argparse parser."""
   parser = commandline.ArgumentParser(description=__doc__)