Lab 4 : dc1.large in Cloudformation may not be available  

When using NodeType: dc1.large I got the following error
```
CloudFormation Event CREATE_FAILED

You do not have access to node type dw2.large. Choose another node type (Service: AmazonRedshift; Status Code: 400; Error Code: NumberOfNodesQuotaExceeded; Request ID: d0585f06-691a-11ea-aff2-b95586675298)
--
```
Use ds2.xlarge or edit CloudFormation to use newer node type