Fix for [#26254] Rendering problem with group-instances of particle-instances

* Render level derived mesh (needed for proper hair rendering) was only calculated before duplication code if the particle object was a level 0 duplicator, so particles creating objects inside a dupligroup didn't work.
* I really don't see the need for the level == 0 check, so I just removed it and after some quick tests can't see any negative effects. If the check is needed for some case though then a more complicated test is needed to handle all cases.

source/blender/render/intern/source/convertblender.c

@@ -4744,7 +4744,7 @@ static void dupli_render_particle_set(Render *re, Object *ob, int timeoffset, in
 			}
 		}
 
-		if(level == 0 && enable) {
+		if(enable) {
 			/* this is to make sure we get render level duplis in groups:
 			* the derivedmesh must be created before init_render_mesh,
 			* since object_duplilist does dupliparticles before that */