python2.5 PyArg_ParseTuple fix
Python 2.5 doesn't like it when we mix str objects and the "t#" format
in PyArg_ParseTuple. Change it to use "s#". Tested with python 2.3, 2.4
and 2.5.
abort: Failed to parse .../t/.hg/hgrcFile contains no section headers.file: .../t/.hg/hgrc, line: 1'invalid\n'