SingleLayerWater is rendering brighter shallow water with fog

Shallow water areas in scenes with exponential height fog will be brighter than they should be. Possibly due to the fog being applied twice in the SingleLayerWater shading model.

1. Open QA-WaterWorks in QAGame.
2. Add Exponential Height Fog to the scene and set the Density to 1.0
3. The scene should now appear very dark.
4. Move the camera upwards and look down at where the water meets land.
5. If the water looks very dark and there is a hard cutoff, you have reproduced the problem. If there is a smooth transition between water and land, the fix worked.