Add new OpenHPC.repo to pin the ohpc release to update 5

Created by: jprorama

Use an explicit url in the Update stanza of the yum repo file to prevent ohpc packages from going past the 1.3.5 release

This release appears to have introduce an error with slurm environment setup that is impacting open on demand starting a VNC job due to an exported job environment that does not include HOME or other critical variables.