bootstrap-scrollspy.js: enable work around for body { height: 100%; }

Created by: Pfiver

I might have missed some other easy way to fix this but this works, after hours of tracking it down.

In case you define

html, body {height: 100%;}

in your css, as suggeted on http://www.cssstickyfooter.com/using-sticky-footer-code.html

which is working fine otherwise, scrollspy breaks.

This patch enables you to work around that issue by calling scrollspy like this:

$(window).scrollspy({wrap: $('#wrap')[0]});