fix(data-driven-lab): bug fix
fix(data-driven-lab): bug fix

Corrected reference to events in function to store data in IndexedDB

Change-Id: Ib50f49ac9eb4b50b26a10785342bcf835a4ae621

googlecodelabs/workbox-lab,googlecodelabs/workbox-indexeddb,googlecodelabs/workbox-indexeddb,googlecodelabs/workbox-lab,googlecodelabs/amp-pwa-workbox,googlecodelabs/amp-pwa-workbox