damage stuff in any part of the cell; don't put smudge in water

OpenRA.Game/Combat.cs

@@ -76,13 +76,10 @@ namespace OpenRA
 				case DamageModel.PerCell:
 					{
 						foreach (var t in world.FindTilesInCircle(targetTile, warhead.SmudgeSize[0]))
-						{
-							var x = Util.CenterOfCell(t);
-							foreach (var unit in world.FindUnits(x, x))
+							foreach (var unit in world.FindUnits(Game.CellSize * t, Game.CellSize * (t + new float2(1,1))))
 								unit.InflictDamage(args.firedBy,
 									(int)(warhead.Damage * warhead.EffectivenessAgainst(
 									unit.Info.Traits.Get<OwnedActorInfo>().Armor)), warhead);
-						}
 					} break;
 			}
 		}