74c3c19765
Export qemu_opt_find for qcow2 driver using it. After replacing QEMUOptionParameter with QemuOpts, qcow2 driver will use qemu_opt_find to judge if an option is explicitly set, to replace the usage of .assigned in QEMUOptionParameter. Signed-off-by: Chunyan Liu <cyliu@suse.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>