fix vpc name format

Author: ddelgrosso1

google/cloud/storage/tests/bucket_integration_test.cc

@@ -574,10 +574,10 @@ TEST_F(BucketIntegrationTest, PatchIpFilter) {
   ip_filter.allow_cross_org_vpcs = true;
   ip_filter.public_network_source =
       BucketIpFilterPublicNetworkSource{{"1.2.3.4/32"}};
+  auto network_name = "projects/" + project_id_ + "/global/networks/default";
   ip_filter.vpc_network_sources =
       absl::make_optional<std::vector<BucketIpFilterVpcNetworkSource>>(
-          {BucketIpFilterVpcNetworkSource{"projects/p/global/networks/n",
-                                          {"5.6.7.8/32"}}});
+          {BucketIpFilterVpcNetworkSource{network_name, {"5.6.7.8/32"}}});
 
   auto patched = client.PatchBucket(
       bucket_name, BucketMetadataPatchBuilder().SetIpFilter(ip_filter));