Closing a streaming write handle sends a clean EOF to the backend
upload, so a writer which knows its data source failed part way through
had no way to stop the truncated file being stored as if it were
complete.
CloseWithError closes the handle failing the upload with the given
reason instead. EOF-like reasons are rewritten so the layers reading
the pipe can't mistake them for a clean end of stream and commit the
partial file.
Needed by serve s3 to abort interrupted PUTs - see #9718
Nick Craig-Wood
2f0657c35b