qemu.py: always cleanup on shutdown()

qemu.py: always cleanup on shutdown()

Currently we only cleanup on shutdown() if the VM is running.

To make sure we will always cleanup, this patch makes the
self._load_io_log() and the self._post_shutdown() to
always be called on shutdown(), regardless the VM running state.

Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Amador Pahim <apahim@redhat.com>
Message-Id: <20180122205033.24893-4-apahim@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>