installer: fix installers for node.js rename

This commit completes the io.js to Node.js rename in the
Windows installer.

Fixes: https://github.com/nodejs/node/issues/2418
PR-URL: https://github.com/nodejs/node/pull/2367


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: João Reis <reis@janeasystems.com>