The new VIR_CONNECT_COMPARE_CPU_FAIL_INCOMPATIBLE flag for
virConnectCompareCPU can be used to get an error
(VIR_ERR_CPU_INCOMPATIBLE) describing the incompatibility instead of the
usual VIR_CPU_COMPARE_INCOMPATIBLE return code.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>