title: Elasticsearch snapshot restore throwing "repository missing" exception
body: <pre>"error": "RemoteTransportException[[Francis Underwood][inet[/xx.xx.xx.xx:9300]][cluster/snapshot/get]]; nested: RepositoryMissingException[[xxxxxxxxx] missing]; ",
     "status": 404
  
  </pre>
  
  <p>I am also unable to create new snapshot repository for snapshots on s3</p>
  
  <pre>
      PUT _snapshot/bkp_xxxxx_master
      {
      "type": "s3",
      settings": {
      "region": "us-xxxx-x",
      "bucket": "elasticsearch-backups",
      "access_key": "xxxxxxxxxxxx",
      "secret_key": "xxxxxxxxxxxxxxxxxxx"
          }
      }
  </pre>
  
  <p>Response I receive for this PUT is below:</p>
  
  <pre>
      {
     "error": "RemoteTransportException[[Francis Underwood][inet[/xx.xx.xx.xx:9300]][cluster/repository/put]]; nested: RepositoryException[[bkp_xxxxxxx_master] failed to create repository]; nested:'AbstractMethodError[org.elasticsearch.cloud.aws.blobstore.S3BlobStore.immutableBlobContainer(Lorg/elasticsearch/common/blobstore/BlobPath;)Lorg/elasticsearch/common/blobstore/ImmutableBlobContainer;]; ",
     "status": 500
  }
  </pre>
  
  <p>Thanks in advance!</p>