Host-model CPU definitions (and domain capabilities) will use the
original CPU models (without noTSX in their name) and explicitly disable
hle and rtm features. This way domains with host-model CPUs will be
migratable even to older versions of libvirt which do not support the
noTSX model variants.

The new models will be advertised in host capabilities and they may
be used explicitly with custom CPUs.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NChristian Ehrhardt <christian.ehrhardt@canonical.com>
Tested-by: NChristian Ehrhardt <christian.ehrhardt@canonical.com>