SH-1427 Fix for shader compilation failure when detail set to "mid"

indra/newview/app_settings/shaders/class1/windlight/atmosphericsHelpersV.glsl

@@ -38,7 +38,7 @@ vec3 atmosAffectDirectionalLight(float lightIntensity)
 
 vec3 atmosGetDiffuseSunlightColor()
 {
-	return sunlight_color.rgb;
+	return sunlight_color_copy.rgb;
 }
 
 vec3 scaleDownLight(vec3 light)