hook_faqemu: using libvirt instead of hacking it

Passing -no-kvm / -enable-kvm directly to qemu is a rather bad idea,
if you do not change domain type. These options should be set by
libvirt upon the domain type: domain type='kvm' will engage kvm
and domain type='qemu' will use faqemu correctly in all libvirt
versions on any host type.

Since vdsm-faqemu do not provide nothing but this option hack,
it can be safely removed, libvirt will do all the work. Beside of
that, there is no need for /dev/kvm creation hack, since domain
type='qemu' does not check it on the startup.

Signed-off-by: Peter V. Saveliev <peet@redhat.com>
Change-Id: I85f0208bf55f26c5bd146e3a81f28fdc56b8c5ce
Reviewed-on: http://gerrit.ovirt.org/12084
Reviewed-by: Vinzenz Feenstra <vfeenstr@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>