OcclusionBuffer.cpp: fix warning
OcclusionBuffer.cpp: fix warning

bacsmar/Urho3D,PredatorMF/Urho3D,PredatorMF/Urho3D,eugeneko/Urho3D,PredatorMF/Urho3D,PredatorMF/Urho3D,urho3d/Urho3D,urho3d/Urho3D,bacsmar/Urho3D,eugeneko/Urho3D,urho3d/Urho3D,eugeneko/Urho3D,urho3d/Urho3D,orefkov/Urho3D,bacsmar/Urho3D,orefkov/Urho3D,orefkov/Urho3D,eugeneko/Urho3D,orefkov/Urho3D,bacsmar/Urho3D