Make arg parser return growable list of rest arguments.

utils/pub/pub.dart

Index: utils/pub/pub.dart
diff --git a/utils/pub/pub.dart b/utils/pub/pub.dart
index 122a962d39ec2dec8aa18411fc563a8383e2bab1..f18d9c9a45c6a98561859d631ae03ffbf993c1eb 100644
--- a/utils/pub/pub.dart
+++ b/utils/pub/pub.dart
@@ -227,7 +227,7 @@ abstract class PubCommand {
     globalOptions = globalOptions_;
 
     try {
-     commandOptions = commandParser.parse(commandArgs);
+      commandOptions = commandParser.parse(commandArgs);
     } on FormatException catch (e) {
       log.error(e.message);
       log.error('Use "pub help" for more information.');