Upgrade to use stable `package:googleapis/v1.dart` of datastore

test/datastore/e2e/datastore_test_impl.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library datastore_test;
 
 /// NOTE: In order to run these tests, the following datastore indices must
 /// exist:
 /// $ cat index.yaml
 /// indexes:
@@ skipping 226 matching lines @@
             unnamedEntities5, transactional: true, xg: true).then((keys) {
           return delete(keys).then((_) {
             return lookup(keys).then((List<Entity> entities) {
               entities.forEach((Entity e) => expect(e, isNull));
             });
           });
         });
       });
 
       test('negative_insert__incomplete_path', () {
-        expect(datastore.commit(inserts: unnamedEntities1),
-                                throwsA(isApplicationError));
+        expect(() => datastore.commit(inserts: unnamedEntities1),
+               throwsA(isApplicationError));
       });
 
       test('negative_insert_transactional_xg', () {
         return testInsertNegative(
             unnamedEntities26, transactional: true, xg: true);
       });
 
       test('negative_insert_20000_entities', () {
         // Maybe it should not be a [DataStoreError] here?
         // FIXME/TODO: This was adapted
@@ skipping 853 matching lines @@
 main() {
   var scopes = datastore_impl.DatastoreImpl.SCOPES;
 
   withAuthClient(scopes, (String project, httpClient) {
     var datastore = new datastore_impl.DatastoreImpl(httpClient, 's~$project');
     return cleanupDB(datastore, null).then((_) {
       return runE2EUnittest(() => runTests(datastore, null));
     });
   });
 }