FakeS3 doesn't support storage classes other than STANDARD

[loopsysdev]

FakeS3 only supports the STANDARD class of storage. Running the following:

aws --endpoint-url <fakes3 url> s3 cp /tmp/foo s3://bucket-name/foo --storage-class REDUCED_REDUNDANCY

results in a key in FakeS3 with storage class standard:

> aws --endpoint-url http://s3.service.loop:8085 s3api list-objects --bucket bucket-name
{
    "Contents": [
        {
            "LastModified": "2016-06-16T07:54:48.573Z", 
            "ETag": "\"4f13dcb32c7ae164033a25a178533b67\"", 
            "StorageClass": "STANDARD", 
            "Key": "foo", 
            "Owner": {
                "DisplayName": "You", 
                "ID": "abc"
            }, 
            "Size": 28948
        }
    ]
}

However, going to the FakeS3 directory structure and finding the metadata for the key shows the following:

---
:md5: 4f13dcb32c7ae164033a25a178533b67
:content_type: 
:size: 28948
:modified_date: '2016-06-16T07:54:48.573Z'
:amazon_metadata:
  storage-class: REDUCED_REDUNDANCY
:custom_metadata: {}

The problem seems to be here, where the storage class is hard-coded at reporting time.