Test case for grafting onto a parent that was itself grafted.
Test repository by: Anders Pilegaard <arrowyard@gmail.com>
Test case by: me
Branch b3's preferred parent is b1 and b1's preferred parent is b2.
Since b1 is grafted to b2 first, b1 is not found when b3's preferred
parent is sought. This results in a non-optimal creation of branch b3
via a copy from trunk followed by a copy of file2 from b1.
git-svn-id: http://cvs2svn.tigris.org/svn/cvs2svn/trunk@5313 be7e6eca-30d4-0310-a8e5-ac0d63af7087