After commit be9a56e5e3ced5d0d668fa24e4c65ae928f2e25a in qtbase, this is
not needed anymore. Instead the resource system injects the plugin entry
point with a reference to all resources.

Change-Id: I09efba67c3d2e9b68b73707101f1b8cc22284131
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>