flags: account for flag change when tracking rename relevant to merge There are some logic filtering rename to the one relevant to the merge. That logic was oblivious of flag change, leading to exec flag being dropped when merged with a renamed. There are two others bugs affecting this scenario. This patch fix the was where there is not modification involved except for the flag change. Fixes for the other bug are coming in later changesets. Differential Revision: https://phab.mercurial-scm.org/D8531