Fixes a problem with unclosed streams

The streams don't get closed during processing and so stay open and thus cause the test ReplicationTest/testPushReplicationCanMissDocs to fail on Windows but more general mean that anytime, anyone ever uses multi-part (which is used, for example, by the pusher) then the streams will be locked forever and attachment cleanup isn't possible.
Fixing my stupid bug

Thanks for finding it!
Merge pull request #229 from yaronyg/patch-2

Fixes a problem with unclosed streams