The cancel button breaks if "destination" has a query string

If I am on mysite.com/file/1/edit?destination=foo/bar%3Fvar1%3Dxxx then the cancel button does not work properly because the query string from destination is encoded when it is included in the #href property of the $form['cancel'] element. Thats a bit of a mouth-full, but basically we need to split up the query string
and path from the destination.

Note: My real-world case here is that I created a view of files with exposed filters and an edit link in order to customize the table found at /admin/content/file