[PATCH] quote_path: convert empty path to "./"

Now that we are correctly removing leading prefixes from files in git status, there is a degenerate case: the directory matching the prefix. Because we show only the directory name for a directory that contains only untracked files, it gets collapsed to an empty string.

Example:

  $ git init
  $ mkdir subdir
  $ touch subdir/file
  $ git status
  ...
  # Untracked files:
  #   (use "git add <file>..." to include in what will be committed)
  #
  #       subdir/

  So far, so good.

  $ cd subdir
  $ git status
  ....
  # Untracked files:
  #   (use "git add <file>..." to include in what will be committed)
  #
  #

  Oops, that's a bit confusing.

  This patch prints './' to show that there is some output.

--- I think it looks a bit ugly because it is so small (though just '.' was even worse). But I don't see what else would make sense.

 wt-status.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)