git-branch: display "was sha1" on branch deletion rather than just "sha1"

Make it more pleasant to read about a branch deletion by adding "was".
Jeff King suggested this, and I ignored it.  He was right.

Update t3200 test again to match the change in output.

Signed-off-by: Brandon Casey <drafnel@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>