Sorry, my mistake. RHV 4.2 does not support EL6 nodes. Updating bug description.
Was able to successfully import a RHEL6 (kernel 2.6.32-696.20.1.el6.x86_64) RHGS 3.4 cluster with interim build (glusterfs-3.12.2-6) on RHGS-C. The nodes were installed and came up successfully, and all the volume and related cluster information showed correctly. No errors were seen in logs. Moving this bug to verified in RHGS 3.4.0.