Removed confirmation message from RMA edit page

When I tried to confirm (mark as received) a RMA a javascript confirm popup shows up twice.
After that the page did not reload, saw a quick "Loading" message but nothing happened.
Same if you press the Cancel button.

I tested this and some how the `:data => { :confirm => Spree.t(:are_you_sure) }` in the button_link_to tags causes this behavior.

I removed the confirm messages and the returns works perfect again.