reflog-walk: clean up "flag" field of commit_reflog struct
When we prepare to walk a reflog, we parse the specification and pull some information from it, such as which reflog to look in (e.g., HEAD), and where to start (e.g., HEAD@{10} or HEAD@{yesterday}). The resulting struct has a "recno" field to show where in the reflog we are starting. It also has a "flag" field; if true, it means the recno field came from parsing a date like HEAD@{yesterday}. There are two problems with this: 1. "flag" is an absolutely terrible name, as it conveys nothing about the meaning 2. you can tell "HEAD" from "HEAD@{yesterday}", but you can't differentiate "HEAD" from "HEAD{0}" This patch converts the flag into a tri-state (and gives it a better name!). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>