2-2 fix for customer returns Admin UI

"button_to" cannot accept the "params" argument in Rails 4.0.
See http://api.rubyonrails.org/v4.1.4/classes/ActionView/Helpers/UrlHelper.html#method-i-button_to
vs http://api.rubyonrails.org/v4.0.5/classes/ActionView/Helpers/UrlHelper.html#method-i-button_to