SL-11656 Alpha textures with Alpha mask cutoff of 255 look glitchy while ALM is off.

indra/newview/app_settings/shaders/class1/lighting/lightAlphaMaskF.glsl

@@ -41,12 +41,12 @@ void default_lighting()
 {
 	vec4 color = diffuseLookup(vary_texcoord0.xy);
 	
-	color *= vertex_color;
-
 	if (color.a < minimum_alpha)
 	{
 		discard;
 	}
+	
+	color *= vertex_color;
 
 	color.rgb = atmosLighting(color.rgb);