fix crash when no -u given

wccl-apps/wccl-rules.cpp

@@ -231,7 +231,9 @@ int main(int argc, char** argv)
 	try {
 		const Corpus2::Tagset& tagset = Corpus2::get_named_tagset(tagset_load);
 		RuleRunner runner(tagset);
-		runner.set_tag_rule_iterations(vm["until-done-iterations"].as<int>());
+		if (vm.count("until-done-iterations")) {
+			runner.set_tag_rule_iterations(vm["until-done-iterations"].as<int>());
+		}
 		runner.use_progress(progress);
 		foreach (const std::string& file, ccl_files) {
 			std::pair<int,int> res = runner.load_more_rules(file);