Make the file storage use the streaming buffer API.
As the individual file chunks were not needed by themselves, this
approach uses a chunkless implementation.
The SCStreamingBuffer call now also returns two booleans:
data, data_open, data_close = SCStreamingBuffer()
The first indicates this is the first data of this type for this
TCP session or HTTP transaction.
The second indicates this is the last data.
Ticket #1317.