release.py: Unbreak the 'write-downloads' command.
release.py: Unbreak the 'write-downloads' command.

The failure mode was:

    Traceback (most recent call last):
      File "./release.py", line 1136, in <module>
        main()
      File "./release.py", line 1132, in main
        args.func(args)
      File "./release.py", line 812, in write_downloads
        sha1info = get_sha1info(args, replace=True)
      File "./release.py", line 764, in get_sha1info
        target = get_target(args)
      File "./release.py", line 227, in get_target
        if args.target:
    AttributeError: 'Namespace' object has no attribute 'target'

* tools/dist/release.py
  (main.'write-downloads'): Take the --target option.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1800580 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion