Confusing exception when trying to start 'burrowd --help'

[Erik Swanson]

Burrowd should print a helpful message when invoked with '-h' or '--help' (or anything that isn't a config file) in its arguments.
The current behavior results in an uninformative traceback:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/Users/erik/Checkouts/burrow/burrow/server.py", line 84, in <module>
    Server(sys.argv[1:]).run()
  File "/Users/erik/Checkouts/burrow/burrow/server.py", line 38, in __init__
    self._config = burrow.config.load_config_files(config_files)
  File "/Users/erik/Checkouts/burrow/burrow/config.py", line 80, in load_config_files
    logging.config.fileConfig(config_files)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/logging/config.py", line 70, in fileConfig
    formatters = _create_formatters(cp)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/logging/config.py", line 106, in _create_formatters
    flist = cp.get("formatters", "keys")
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/ConfigParser.py", line 567, in get
    raise NoSectionError(section)
ConfigParser.NoSectionError: No section: 'formatters'