Fixes git-rstatus for windows

This fixes 'git rstatus' for Windows by hiding the output of 'mktemp'. Another thing to make it work on Windows is download the binary of 'mktemp' for Windows from the GnuWin32 project:

http://gnuwin32.sourceforge.net/packages/mktemp.htm

Place it in C:\Program Files\Git\bin

Note: This has not been tested on any other operating system besides Windows 7 Professional x86, but I believe none of the changes are breaking to any other OS.