Hard-coded cluster name in ohpc_install role

[mikerenfro]

https://github.com/XSEDE/CRI_XCBC/blob/32d3dbbcd7da0025b86c1a9f1de4fe42e7c9ddfc/roles/ohpc_install/files/xcbc-example.cfg#L13

Probably should follow the method used for slurm.conf, and convert this file into a template referencing the cluster_name variable Could do similarly with variables for the test user and the Slurm account for its association.