gsutil: hide traceback on Ctrl+C

The traceback from our thin gs module isn't useful, so hide it by
default.

BUG=None
TEST=ran gsutil & Ctrl+C it

Change-Id: Iacb622abf90b74090fd4fdbfcea77b451b9fe982
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3614121
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Ram Chandrasekar <rchandrasekar@google.com>
Commit-Queue: Ram Chandrasekar <rchandrasekar@google.com>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/gsutil.py b/scripts/gsutil.py
index da1b375..2a69287 100644
--- a/scripts/gsutil.py
+++ b/scripts/gsutil.py
@@ -7,10 +7,17 @@
 This takes care of downloading the pinned version we use in chromite.
 """
 
+import logging
+import signal
+
 from chromite.lib import gs
 
 
 def main(argv):
   ctx = gs.GSContext(retries=0)
-  return ctx.DoCommand(
-      argv, print_cmd=False, stderr=None, check=False).returncode
+  try:
+    return ctx.DoCommand(
+        argv, print_cmd=False, stderr=None, check=False).returncode
+  except KeyboardInterrupt:
+    logging.debug('Aborted due to keyboard interrupt.')
+    return 128 + signal.SIGINT