fix(position): remove deprecated body scrollTop and scrollLeft

Fixes #1658
Closes #1677

Author: mvhecke

src/position/position.js

@@ -72,8 +72,8 @@ angular.module('ui.bootstrap.position', [])
         return {
           width: boundingClientRect.width || element.prop('offsetWidth'),
           height: boundingClientRect.height || element.prop('offsetHeight'),
-          top: boundingClientRect.top + ($window.pageYOffset || $document[0].body.scrollTop || $document[0].documentElement.scrollTop),
-          left: boundingClientRect.left + ($window.pageXOffset || $document[0].body.scrollLeft  || $document[0].documentElement.scrollLeft)
+          top: boundingClientRect.top + ($window.pageYOffset || $document[0].documentElement.scrollTop),
+          left: boundingClientRect.left + ($window.pageXOffset || $document[0].documentElement.scrollLeft)
         };
       }
     };