Drop support for older Barback versions.

test/transformer/prints_a_transform_error_in_apply_test.dart

Index: test/transformer/prints_a_transform_error_in_apply_test.dart
diff --git a/test/transformer/prints_a_transform_error_in_apply_test.dart b/test/transformer/prints_a_transform_error_in_apply_test.dart
index 0d2c25a84fa3718f4b9db7417474596e1dcb6291..d4cb53306dacde21691a5cd8c232b01030529934 100644
--- a/test/transformer/prints_a_transform_error_in_apply_test.dart
+++ b/test/transformer/prints_a_transform_error_in_apply_test.dart
@@ -23,28 +23,26 @@ class RewriteTransformer extends Transformer {
 """;
 
 main() {
-  withBarbackVersions("any", () {
-    integration("prints a transform error in apply", () {
-      d.dir(appPath, [
-        d.pubspec({
-          "name": "myapp",
-          "transformers": ["myapp/src/transformer"]
-        }),
-        d.dir("lib", [d.dir("src", [
-          d.file("transformer.dart", transformer)
-        ])]),
-        d.dir("web", [
-          d.file("foo.txt", "foo")
-        ])
-      ]).create();
-
-      createLockFile('myapp', pkg: ['barback']);
-
-      var server = pubServe();
-      server.stderr.expect(emitsLines(
-          'Build error:\n'
-          'Transform Rewrite on myapp|web/foo.txt threw error: oh no!'));
-      endPubServe();
-    });
+  integration("prints a transform error in apply", () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "transformers": ["myapp/src/transformer"]
+      }),
+      d.dir("lib", [d.dir("src", [
+        d.file("transformer.dart", transformer)
+      ])]),
+      d.dir("web", [
+        d.file("foo.txt", "foo")
+      ])
+    ]).create();
+
+    createLockFile('myapp', pkg: ['barback']);
+
+    var server = pubServe();
+    server.stderr.expect(emitsLines(
+        'Build error:\n'
+        'Transform Rewrite on myapp|web/foo.txt threw error: oh no!'));
+    endPubServe();
   });
 }