path-utils test: rename mingw_path function to print_path

mingw_path was introduced in abd4284 to output a mangled path as it is
passed as an argument to main(). But the name is misleading because
mangling does not come from MinGW, but from MSYS [1]. As abd4284 does not
introduce any MSYS or MinGW specific code but just prints out argv[2] as
it is passed to main(), give the function the more generic and less
confusing name "print_path".

[1] http://www.mingw.org/wiki/Posix_path_conversion

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>