Complimenting the existing 'lstrip=<N>' option, add an 'rstrip=<N>'
option which strips `<N>` slash-separated path components from the end
of the refname (e.g., `%(refname:rstrip=2)` turns `refs/tags/foo` into
`refs`).
Signed-off-by: Karthik Nayak <Karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>