qemu: Add missing on_crash lifecycle type
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1201760
    
    When the domain "<on_crash>coredump-destroy</on_crash>" is set, the
    domain wasn't being destroyed, rather it was being rebooted.
    
    Add VIR_DOMAIN_LIFECYCLE_CRASH_COREDUMP_DESTROY to the list of
    on_crash types that cause "-no-reboot" to be added to the qemu
    command line.