Merge branch 'sj/untracked-files-in-submodule-directory-is-not-dirty'

"git diff" showed a submodule working tree with untracked cruft as "Submodule commit <objectname>-dirty", but a natural expectation is that the "-dirty" indicator would align with "git describe --dirty", which does not consider having untracked files in the working tree as source of dirtiness. The inconsistency has been fixed. * sj/untracked-files-in-submodule-directory-is-not-dirty: diff: do not show submodule with untracked files as "-dirty"