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

https://issues.apache.org/jira/browse/LIBCLOUD-639
Refer to my commit message:
"Don't send one byte at a time, read the iterator in chunks and fill the chunks, otherwise it turns a 1.6MB file into more than 400MB (when I gave up and killed the request)."