Only install qemu workaround on RHEL 6.3

This was entered as a workaround for libvirt on RHEL 6.3 and is
no longer needed on RHEL 6.4
https://bugzilla.redhat.com/show_bug.cgi?id=912702

Change-Id: I1338bfd6fda23e9326f244d5f98329e761d8f363