[BUG] a couple of stgit bugs

Here are another couple of (probably long-standing) bugs I noticed
today on 0.11, but which still hold on current HEAD:

- "stg status <files>" does not restrict output to listed files/dirs:

yann/git/stgit$ ./stg status stgit/
? contrib/stg-cvs.new
? contrib/stg-cvs.orig
? contrib/stg-cvs.rej
? stgit/commands/pick.py.orig
? stgit/stack.py.orig


- "stg refresh" still does not work in subdir:

git/stgit/examples$ ../stg refresh
Checking for changes in the working directory... done
Refreshing patch "test"...error: examples/examples/gitconfig: does not exist and --remove not passed
fatal: Unable to process file examples/gitconfig
stg refresh: Failed git-update-index

Traceback (most recent call last):
  File "../stg", line 43, in ?
    main()
  File "/export/work/yann/git/stgit/stgit/main.py", line 262, in main
    command.func(parser, options, args)
  File "/export/work/yann/git/stgit/stgit/commands/refresh.py", line 145, in func
    backup = True, sign_str = sign_str)
  File "/export/work/yann/git/stgit/stgit/stack.py", line 667, in refresh_patch
    committer_email = committer_email)
  File "/export/work/yann/git/stgit/stgit/git.py", line 540, in commit
    changes = update_cache(files)
  File "/export/work/yann/git/stgit/stgit/git.py", line 523, in update_cache
    raise GitException, 'Failed git-update-index'
stgit.git.GitException: Failed git-update-index

Best regards,
-- 
Yann.