In this commit
e5974ac4b0 s3: use PutObject from the aws SDK to upload single part objects
rclone was made to upload objects to s3 using PUT requests rather than
using signed uploads.
However this change missed the fact that there is a supported way to
do this in the SDK using the SetStreamingBody method on the Request.
This therefore reverts a lot of the previous commit to do with making
an unsigned connection and other complication and uses the SDK
facility.