jsonrpc: StorageDomain_deactivate

Align naming between API.py and schema.

Change-Id: Ibb709aee2d5de26f2eff5775fd574fb96582174f
Signed-off-by: pkliczewski <piotr.kliczewski@gmail.com>
Reviewed-on: http://gerrit.ovirt.org/35538
Reviewed-by: Adam Litke <alitke@redhat.com>