Revert cluster-workerocs.yaml machinesets back to using AWS region us-east-1

[netzzer]

Do you need more detailed steps on an existing section? Please describe.
The section https://github.com/red-hat-storage/ocs-training/blob/master/ocp4ocs4/ocs4.adoc#scale-ocp-cluster-and-add-3-new-nodes needs to use AWS region us-east-1 to match instructions of using RHPDS workshop named 'OpenShift 4.2 Workshop'. Currently cluster-workerocs.yaml is creating machines/machinesets in us-east-2 region.

This yaml file is correct for creating new machines (workerocs) in us-east-1:
https://github.com/red-hat-storage/ocs-training/blob/master/ocp4ocs4/cluster-workerocs-us-east-1.yaml

Describe what you would like to see
Match the training content in ocs4.adoc which is all based on AWS region us-east-1.