Commit de51dc9c primarily added
virConnectGetCPUModelNames as libvirt.getCPUModelNames(conn, arch)
instead of libvirt.virConnect.getCPUModelNames(arch) so revert the code
that does the former while leaving the code that does the later.

This is the rest of the patch that was ACK'd by Dan but I committed only
the partial patch in 6a8b8ae4.