Drop support for older Barback versions.

test/transformer/a_transformer_rejects_its_config_test.dart

Index: test/transformer/a_transformer_rejects_its_config_test.dart
diff --git a/test/transformer/a_transformer_rejects_its_config_test.dart b/test/transformer/a_transformer_rejects_its_config_test.dart
index bd28bbcf22ef0db4d62e8dba350960dbc966c62f..4ca939c504b4af248f795a7f323c56f26a16a185 100644
--- a/test/transformer/a_transformer_rejects_its_config_test.dart
+++ b/test/transformer/a_transformer_rejects_its_config_test.dart
@@ -26,24 +26,22 @@ class RejectConfigTransformer extends Transformer {
 """;
 
 main() {
-  withBarbackVersions("any", () {
-     integration("a transformer can reject is configuration", () {
-       d.dir(appPath, [
-         d.pubspec({
-           "name": "myapp",
-           "transformers": [{"myapp/src/transformer": {'foo': 'bar'}}]
-         }),
-         d.dir("lib", [d.dir("src", [
-           d.file("transformer.dart", REJECT_CONFIG_TRANSFORMER)
-         ])])
-       ]).create();
-
-       createLockFile('myapp', pkg: ['barback']);
-
-       var pub = startPubServe();
-       pub.stderr.expect(endsWith('Error loading transformer: I hate these '
-           'settings!'));
-       pub.shouldExit(1);
-     });
-  });
+   integration("a transformer can reject is configuration", () {
+     d.dir(appPath, [
+       d.pubspec({
+         "name": "myapp",
+         "transformers": [{"myapp/src/transformer": {'foo': 'bar'}}]
+       }),
+       d.dir("lib", [d.dir("src", [
+         d.file("transformer.dart", REJECT_CONFIG_TRANSFORMER)
+       ])])
+     ]).create();
+
+     createLockFile('myapp', pkg: ['barback']);
+
+     var pub = startPubServe();
+     pub.stderr.expect(endsWith('Error loading transformer: I hate these '
+         'settings!'));
+     pub.shouldExit(1);
+   });
 }