qemu: Restore lost shutdown reason

qemu: Restore lost shutdown reason

When qemuProcessReconnectHelper was introduced (commit d38897a5d)
reconnection failure used VIR_DOMAIN_SHUTOFF_FAILED; however, that
was changed in commit bda2f17d to either VIR_DOMAIN_SHUTOFF_CRASHED
or VIR_DOMAIN_SHUTOFF_UNKNOWN.

When QEMU_CAPS_NO_SHUTDOWN checking was removed in commit fe35b1ad6
the conditional state was just left at VIR_DOMAIN_SHUTOFF_CRASHED.

So introduce qemuDomainIsUsingNoShutdown which will manage the
condition when the domain was started with -no-shutdown so that
when/if reconnection failure occurs we can restore the decision
point used to determine whether CRASHED or UNKNOWN is provided.

Signed-off-by: John Ferlan <jferlan@redhat.com>
ACKed-by: Michal Privoznik <mprivozn@redhat.com>