Update utls to return proper exit code when fetch-configlet fails

Author: Stargator

bin/check_formatting.dart

@@ -5,7 +5,7 @@ Future main() async {
   final CommonUtils utils = CommonUtils();
   int errorCode = 0;
 
-  if (utils.fetchConfiglet() == 0) {
+  if (await utils.fetchConfiglet() == 0) {
     print('Checking config.json formatting...');
     errorCode = await utils.runCmdIfExecutable('bin/configlet', ['lint', '--track-id', 'dart', '.']);
 

bin/presubmit.dart

@@ -4,7 +4,7 @@ import 'package:exercism_dart/src/utils.dart';
 Future<Null> main() async {
   final CommonUtils utils = CommonUtils();
 
-  if (utils.fetchConfiglet() == 0) {
+  if (await utils.fetchConfiglet() == 0) {
     print('Formatting config.json...');
     await utils.runCmdIfExecutable('bin/configlet', ['fmt', '.']);
   }

lib/src/utils.dart

@@ -11,12 +11,12 @@ class CommonUtils {
 
   /// Fetches the configlet file if it doesn't exist already, and returns the
   /// exit code.
-  int fetchConfiglet() {
+  Future<int> fetchConfiglet() async {
     final configletFile = File('bin/configlet');
 
     if (!configletFile.existsSync()) {
       print('Fetching configlet...');
-      return _exit(Process.runSync('bin/fetch-configlet', []).exitCode);
+      return _exit(await runCmdIfExecutable('bin/fetch-configlet'));
     }
 
     return 0;