Force entire swap process to be portrait.

Although this is usually regarded as poor form, it is currently better than the alternative which is the whole swap process poohing itself when a device is rotated. In the future, it may be worthwhile investing in designing a proper UX for landscape swap too. However the process of swapping can be quite complex if not presented well, and so it might end up being too much work to maintain two different UXes for landscape and portrait.