[LIBCLOUD-639] Python 3 Error: "Invalid argument %r for b()" when using upload_object_via_stream

https://issues.apache.org/jira/browse/LIBCLOUD-639
To be more explicit, I tested this by watching the python3.4 process in the OSX Activity Monitor > Network > Sent Bytes. Without this fix I saw over 400MB uploaded (when I gave up, debugging later revealed the process sending the bytes one at a time, so probably one per packet with all the associated overheads).

With this fix, the process only uploaded a little over the expected 1.6MB for my test file, which makes sense with typical network overheads (wrapping in packets, <1500 Bytes MTU meaning some fragmentation, etc).