Merge pull request #4762 from Verkister/patch-3

Fixes vis_enabled becoming unobtainable if something happens to apply plane_holder to mob before client

code/modules/mob/login.dm

@@ -50,6 +50,7 @@
 
 	if(!plane_holder) //Lazy
 		plane_holder = new(src) //Not a location, it takes it and saves it.
+	if(!vis_enabled)
 		vis_enabled = list()
 	client.screen += plane_holder.plane_masters
 	recalculate_vis()