D24754: Fix KNSCore::Cache fetching when initialising Engine

[Dan Leinir Turthra Jensen]

leinir added reviewers: rikmills, Frameworks, KNewStuff.

REPOSITORY
  R304 KNewStuff

REVISION DETAIL
  https://phabricator.kde.org/D24754

To: leinir, rikmills, #frameworks, #knewstuff
Cc: kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns