[autotest] allow creation of empty shards

BUG=None
TEST=shard_unittest; rpc_interface_unittest

Change-Id: I0eda2bd67ca42cdd8717d16d93a7e228c1439ec2
Reviewed-on: https://chromium-review.googlesource.com/457848
Commit-Ready: Aviv Keshet <[email protected]>
Tested-by: Aviv Keshet <[email protected]>
Reviewed-by: Dan Shi <[email protected]>
diff --git a/frontend/afe/rpc_interface_unittest.py b/frontend/afe/rpc_interface_unittest.py
index 87a8cdc..61c6e53 100755
--- a/frontend/afe/rpc_interface_unittest.py
+++ b/frontend/afe/rpc_interface_unittest.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python2
 # pylint: disable=missing-docstring
 
 import datetime