Don’t throw an exception if already closed.

I am currently chasing a problem in Sone that prevents me from inserting new editions. I created a fresh node for that. The problem surfaces when the TarArchiveOutputStream is closed in SimpleManifestPutter:1118: it closes its internal TarBuffer which in turn already closes the underlying output stream. Afterwards, the TAOS itself closes the output stream again. This output stream, however, is a TempBucketFactory$TempBucket$TempBucketOutputStream which throws an exception in TempBucketFactory:213 if it is already closed. This is in clear violation of Closeable.close() with says “If the stream is already closed then invoking this method has no effect.”