travis: add libvirt 4.5.0 version to build matrix
travis: add libvirt 4.5.0 version to build matrix

Signed-off-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

libvirt/libvirt-python,libvirt/libvirt-python,libvirt/libvirt-python