Render: Remove global RNG usage

We shouldn't be using BI textures anyway. But in any case, adding noise
texture to compositor is doing proper seed updates already, so probably
was already ported to a proper RNG usage.

source/blender/render/intern/source/pipeline.c

@@ -1564,9 +1564,6 @@ static void do_render_composite(Render *re)
 	bNodeTree *ntree = re->scene->nodetree;
 	int update_newframe = 0;
 
-	/* INIT seeding, compositor can use random texture */
-	BLI_srandom(re->r.cfra);
-
 	if (composite_needs_render(re->scene, 1)) {
 		/* save memory... free all cached images */
 		ntreeFreeCache(ntree);