The `rad patch checkout` command would blindly create a branch when
being executed. If there was a branch already existing and user had
committed to that branch, switched without updating the patch, and
then switched back, then they would lose the commit on that branch --
the original commit of the patch would be taken instead.
Fix this by first checking if the branch existed beforehand, and
setting the workspace to use that branch's commit.
Add a test to ensure that this works as expected.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
Fintan Halpenny