Upload enhancement: Allow removal of files from the distro

Upload enhancement: Allow removal of files from the distro

[Christopher Faylor]

I've modified upset to allow the removal of files from the cygwin
distribution.  If you want a file to disappear, upload an empty file
with a leading dash as the filename.  This will caused the corresponding
file in the distribution to be moved to an archive directory.  This
archive directory is only available to people with normal logins to
sourceware.org.

Wildcards are allowed in the filename, so be careful.

Slightly more details on file removal here:
https://sourceware.org/cygwin-apps/package-upload.html

I plan on writing a cron job which deletes old archived files but I
haven't done that yet.  This isn't a sophisticated backup mechanism so
if you delete, recreate, and delete a file you won't be able to get the
file you originally deleted.  I don't expect this to be a common
scenario.

I'm still not entirely wild about this way of handling file removal
so it's likely that something else could show up in the next ten years.
But at least now people can remove files that they don't want.

I've also modified upset so that files will not be moved out of the
upload directories and setup.ini will not be updated if there are any
errors detected.  Hopefully this means that release that people grab
should always be error-free.

Contemplated upcoming change: If you create a !announce file the
contents will eventually be sent to cygwin-announce.  The announcements
will be batched and only sent out when it seems like at least one of the
cygwin mirrors has the release (I won't necessarily know for sure if
the file is there but the chances will be pretty high that it will be).

The announcements will have the name of the maintainer with a from
and reply-to of cygwin <at>... you know.

This change requires some coordination between upset and the mirror
checker but it seems like it would be nice for announcements to go
out after the mirrors have picked up an update.  In theory, the
announcement could even contain a list of mirrors which are likely
to have the update.

cgf