Exception caused by empty files

[jansel]

If you try to commit an empty file, you get the following error:

Traceback (most recent call last):
  File "/home/jansel/testrepo/venv/bin/git-bigstore", line 87, in <module>
    args = parser.parse_args()
  File "/usr/lib/python2.7/argparse.py", line 1701, in parse_args
    args, argv = self.parse_known_args(args, namespace)
  File "/usr/lib/python2.7/argparse.py", line 1733, in parse_known_args
    namespace, args = self._parse_known_args(args, namespace)
  File "/usr/lib/python2.7/argparse.py", line 1942, in _parse_known_args
    stop_index = consume_positionals(start_index)
  File "/usr/lib/python2.7/argparse.py", line 1898, in consume_positionals
    take_action(action, args)
  File "/usr/lib/python2.7/argparse.py", line 1807, in take_action
    action(self, namespace, argument_values, option_string)
  File "/usr/lib/python2.7/argparse.py", line 1096, in __call__
    subnamespace, arg_strings = parser.parse_known_args(arg_strings, None)
  File "/usr/lib/python2.7/argparse.py", line 1733, in parse_known_args
    namespace, args = self._parse_known_args(args, namespace)
  File "/usr/lib/python2.7/argparse.py", line 1942, in _parse_known_args
    stop_index = consume_positionals(start_index)
  File "/usr/lib/python2.7/argparse.py", line 1898, in consume_positionals
    take_action(action, args)
  File "/usr/lib/python2.7/argparse.py", line 1807, in take_action
    action(self, namespace, argument_values, option_string)
  File "/home/jansel/testrepo/venv/bin/git-bigstore", line 45, in __call__
    filter_clean()
  File "/home/jansel/testrepo/venv/local/lib/python2.7/site-packages/bigstore/bigstore.py", line 331, in filter_clean
    firstline = sys.stdin.next()
StopIteration
error: external filter git-bigstore filter-clean failed 1
error: external filter git-bigstore filter-clean failed