Revert "qdev: Free QemuOpts when the QOM path goes away"

This reverts commit abed886ec60cf239a03515cf0b30fb11fa964c44.

This patch originally addressed an issue where a DEVICE_DELETED
event could be emitted (in device_unparent()) before a Device's
QemuOpts were cleaned up (in device_finalize()), leading to a
"duplicate ID" error if management attempted to immediately add
a device with the same ID in response to the DEVICE_DELETED event.

An alternative will be implemented in a subsequent patch where we
defer the DEVICE_DELETED event until device_finalize(), which would
also prevent the race, so we revert the original fix in preparation.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20171016222315.407-3-mdroth@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
