Merge branch 'jk/stash-disable-renames-internally'

When diff.renames configuration is on (and with Git 2.9 and later, it is enabled by default, which made it worse), "git stash" misbehaved if a file is removed and another file with a very similar content is added. * jk/stash-disable-renames-internally: stash: prefer plumbing over git-diff