contrib: fix binary file issues with dumprevlog on Windows
* Fix traceback on dumprevlog: open revlog in mode 'rb' (binary)
* Set stdio to binary mode so that redirected data is not modified
References:
http://selenic.com/pipermail/mercurial/2008-March/018330.html
http://selenic.com/repo/index.cgi/hg/rev/a3fe91b4f6eb