Fix admin auto complete css

See before/after screenshots. First shot is current state, where results are white when hovered with a stray border. This commit simply changes the results to blue when hovered without the border.

![screenshot from 2013-05-28 10 00 45](https://f.cloud.github.com/assets/540762/573228/843d7cfa-c7ac-11e2-9ef2-ac86c3ab52ee.png)

![screenshot from 2013-05-28 11 38 58](https://f.cloud.github.com/assets/540762/573247/b5904a76-c7ac-11e2-94a9-9421622367b0.png)