Guide- link to Windows Binary gives 404

[trevoranderson]

Under section 1, the link to the Windows binary is https://static.rust-lang.org/dist/rust-nightly-install.exe
which gives a 404 error page.

[huonw]

(The problem here is we now have both 32 and 64-bit installers, and thus the URL was split to reflect this. http://www.rust-lang.org/install.html has the correct links, I guess the guide should either link to that page, or have both links.)