qemuDomainGetPreservedMounts: Do not special case /dev
    
    The c1140eb9e got me thinking. We don't want to special case /dev
    in qemuDomainGetPreservedMounts(), but in all other places in the
    code we special case it anyway. I mean,
    /var/run/libvirt/$domain.dev path is constructed separately just
    so that it is not constructed here. It makes only a little sense
    (if any at all).
    
    Signed-off-by: Michal Privoznik <mprivozn@redhat.com>