Merge branch 'jn/unpack-trees-checkout-m-carry-deletion'

"git checkout -m" did not switch to another branch while carrying
the local changes forward when a path was deleted from the index.

* jn/unpack-trees-checkout-m-carry-deletion:
  checkout -m: attempt merge when deletion of path was staged
  unpack-trees: use 'cuddled' style for if-else cascade
  unpack-trees: simplify 'all other failures' case

diff --cc unpack-trees.c
Simple merge