qemu: Align dump options for watchdog and on_crash events

qemu: Align dump options for watchdog and on_crash events

Having on_crash set to either coredump-destroy or coredump-restart
creates core dumps with option memory-only in the directory specified
by auto_dump_path. When a watchdog is triggered with the action dump
the core dump is also placed into the directory specified by auto_dump_path
but is created without the option memory-only.

This patch sets the option memory-only also for core dumps created by the
watchdog event.

Signed-off-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>