Sync with --cache-file fails when file is removed (KeyError in FileLists.fetch_local_list())

[tail]

This sounds similar to #194 and http://sourceforge.net/p/s3tools/mailman/message/32305453/. I looked into the issue a little bit, and I think this has to do with the fact that I'm trying to sync a directory that is periodically removing files, and there are enough large files in the directory that the initial MD5 calculations takes a couple hours. The fix in the aforementioned issues has been to wrap the calls with a try/except on KeyError. I could submit a patch doing the same here, but I'm not sure that doing so is a proper fix.

This was tested against HEAD as of this writing (revision 76eb785). Here is the exception:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    An unexpected error has occurred.
  Please try reproducing the error using
  the latest s3cmd code from the git master
  branch found at:
    https://github.com/s3tools/s3cmd
  If the error persists, please report the
  following lines (removing any private
  info as necessary) to:
   [email protected]

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Invoked as: ./s3cmd --cache-file=/path/to/cache-file -v sync /path/to/sync/ s3://path/to/backup/
Problem: KeyError: 'dev'
S3cmd:   1.5.0-rc1
python:   2.7.3 (default, Apr 10 2013, 06:20:15) 
[GCC 4.6.3]
environment LANG=en_US.UTF-8

Traceback (most recent call last):
  File "./s3cmd", line 2521, in <module>
    rc = main()
  File "./s3cmd", line 2439, in main
    rc = cmd_func(args)
  File "./s3cmd", line 1470, in cmd_sync
    return cmd_sync_local2remote(args)
  File "./s3cmd", line 1440, in cmd_sync_local2remote
    local_list, single_file_local, src_exclude_list = fetch_local_list(args[:-1], is_src = True, recursive = True)
  File "/home/user/s3cmd/S3/FileLists.py", line 321, in fetch_local_list
    _maintain_cache(cache, local_list)
  File "/home/user/s3cmd/S3/FileLists.py", line 277, in _maintain_cache
    cache.unmark_for_purge(local_list[i]['dev'], local_list[i]['inode'], local_list[i]['mtime'], local_list[i]['size'])
KeyError: 'dev'

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    An unexpected error has occurred.
  Please try reproducing the error using
  the latest s3cmd code from the git master
  branch found at:
    https://github.com/s3tools/s3cmd
  If the error persists, please report the
  above lines (removing any private
  info as necessary) to:
   [email protected]
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!