rbt patch can now apply the patches from specific commits from a

review request created with commit history support. As part of this

change, the Patch.get_patch method has been deprecated in favour of

the new Patch.get_patch_data method, which returns a dictionary

instead of a tuple, which is more extendable for the future.

Applied patches from a review request created with commit history.
Attempted to patch a review request created with commit history

  without a commit ID and got the expected error.
Applied a patch from a review request created without commit

  history.