Avoid using deprecated opt in Web-UI
Avoid using deprecated opt in Web-UI

Use new opt instead of deprecated opt to avoid KeyError.

Change-Id: I9bff33eac9c756afb571f81824a8a3242477f321
Closes-Bug: #1777705

openstack/freezer-web-ui,openstack/freezer-web-ui,openstack/freezer-web-ui,openstack/freezer-web-ui