Remove py26 warnings

[joshmoore]

/Library/Python/2.6/site-packages/argparse.py:713: DeprecationWarning: BaseException.message has been deprecated as of Python 2.6
  self.message = message
/Library/Python/2.6/site-packages/argparse.py:720: DeprecationWarning: BaseException.message has been deprecated as of Python 2.6
  return format % dict(message=self.message,
usage: scc [-h] {merge,rebase,clean-sandbox,toke

[sbesson]

Is this issue still valid?

[sbesson]

Closing. We can always reopen if appropriate.