Revert "Fix file upload for S3 regions requiring Signature version 4"
Revert "Fix file upload for S3 regions requiring Signature version 4"

edx/edx-ora2,edx/edx-ora2,EDUlib/edx-ora2,EDUlib/edx-ora2,EDUlib/edx-ora2,edx/edx-ora2,edx/edx-ora2,EDUlib/edx-ora2