This jira is to fix a review comment in
"Add a test to start NFS service with viewfs over a non-hdfs file system. It is ok to add it in a follow up jira."
This test adds 2 tests,
1) test mount of viewfs root, this isn't allowed right now as it is viewfs root is a client side mount only.
2) test mount of filesystem like "file", this isn't supported as well right now.