Merge branch 'ss/describe-dirty-in-the-right-directory'

Merge branch 'ss/describe-dirty-in-the-right-directory'

"git --work-tree=$there --git-dir=$here describe --dirty" did not
work correctly as it did not pay attention to the location of the
worktree specified by the user by mistake, which has been
corrected.

* ss/describe-dirty-in-the-right-directory:
  t6120: test for describe with a bare repository
  describe: setup working tree for --dirty