changed js ordering because of button error

bootstrap button groups (option) are not working anymore: http://stackoverflow.com/a/13539923/1232436

i know this pull request is the opposite of https://github.com/sonata-project/SonataAdminBundle/commit/82793c83ee67142e808b5cd5c950d525e70f9bb2 but i think that this has been solved otherwise (after changing the order back i don't get any background problems as in the screenshot).