Fix import of Make Town Hostile special nodes

Thanks to @fosnola for spotting, and the suggested fix.

src/scenario/special.cpp

@@ -137,7 +137,11 @@ void cSpecial::import_legacy(legacy::special_node_type& old){
 			// 154 was if text response
 		case 155: type = eSpecType::IF_SDF_EQ; break;
 			// 156-169 were undefined
-		case 170: type = eSpecType::MAKE_TOWN_HOSTILE; break;
+		case 170:
+			type = eSpecType::MAKE_TOWN_HOSTILE;
+			ex1a = 0;
+			ex1b = -1;
+			break;
 			// 171-173 were change/swap/transform terrain
 		case 174: type = eSpecType::TOWN_MOVE_PARTY; break;
 		case 175: type = eSpecType::TOWN_HIT_SPACE; break;