Number of streams in SRM2Storage.putFile (rfc)

Defining in a more clever way the number of streams in the SRM2Storage.putFile (and getFile) method

Until now, the way it's done is:

    if sourceSize > self.MAX_SINGLE_STREAM_SIZE:
      nbstreams = 4
    else:
      nbstreams = 1

for the putFile, and the number of streams is set to 1 when using getFile.

This can be inefficient for very large files, especially when storage elements can allow for up to 10 streams (even more in some cases).

Why not have the number of streams defined as the minimum between the MaxNbStreams of the source and the MaxNbStreams of the destination? Those would be defined as Resource properties (like the Host, port, etc.)