In case when ceph is not being used as backend for nova, qemu.conf
file is not distributed, thus some settings, like nova_qemu_vnc_tls do
not have any effect
Closes-Bug: #2003749
Change-Id: I4bc68567cda57d73d030d9a5017cc411f7ee7732
(cherry picked from commit 9843c47e81b2d093af585549af7a9f2fb82e11d1)