ngAttr* directive issue with `href` attribute in IE

This fixes an issue where any form of `ng-attr-href` directive wasn't correctly processed in IE.

I am not sure why there was the special IE condition for the href attribute but `node.getAttribute(name, 2)` doesn't make any sense since it's trying to fetch the binding value from the attribute we are actually trying to populate.

I have removed the special case handling and every unit tests are still passing.

[Issue Plunkr](http://plnkr.co/edit/b1bqBRdfK904xG77BNej?p=preview)