Propagate CacheKeyResolver changes back to the apollo-sample module

[VisheshVadhera]

Realized that we forgot to propagate changes made in #458 back to the apollo-sample module due to which latest builds in #475 & #469 are failing (see this for the exact location of error in the build logs).

@sav007 Maybe you can help us with this one?

[marwanad]

Maybe we should fix through #441.

[VisheshVadhera]

Yeah makes sense. Let me see if I can open a PR.