Removed the extra_dirs and path_file metadata options.

They are unneeded: All this stuff is already done by the
install command which is run by bdist_wininst.

One bug has been fixed:
The root of the fake install tree is install.install_purelib,
not install.install_lib!
They are different if the extra_path option is used in
the setup function.

Rebuild after the changes to wininst.exe.