As this function is excluded using a !defined(OS_MACOSX) in
resource_bundle.cc, we have to add a replacement for it in
resource_bundle_qt.cpp using the inverted logic.

Change-Id: I9b19977c61113280d2af75ba51a5466ecfc0e033
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>