CSIT now matches dut hostname with name of nfs/scratch directory to verify that dut properly mounted nfs directory before proceding with tests. This is broken in Centos 7.

The specific problem is documented in email: https://lists.fd.io/g/csit-dev/message/2519

The problem is caused by commit 86186044368819d66b68732d3e28876e7fcf3561

I had trouble because the ful hostname received from cloud init module in Centos wasn't parsing right causing the host table to be incorrect and routing to fail. At the time, hard coding the dut or tg hostname fixed it but apparently is causing the side affect documented in the email above.