fix crash involving crushing and dead walls

OpenRA.Game/Traits/World/UnitInfluence.cs

@@ -72,8 +72,8 @@ namespace OpenRA.Traits
 				return;
 			else if( influenceNode.actor == toRemove )
 				influenceNode = influenceNode.next;
-			else
-				RemoveInner( ref influenceNode.next, toRemove );
+
+			RemoveInner( ref influenceNode.next, toRemove );
 		}
 
 		public void Update(Actor self, IOccupySpace unit)

OpenRA.Mods.RA/Buildings/Wall.cs

@@ -29,7 +29,6 @@ namespace OpenRA.Mods.RA.Buildings
 		{
 			this.self = self;
 			this.info = info;
-			self.World.WorldActor.Trait<UnitInfluence>().Add(self, self.Trait<Building>());
 		}
 		
 		public IEnumerable<string> CrushClasses { get { return info.CrushClasses; } }