Use prod bootstrap generator

tools/run_tests/xds_test_driver/config/grpc-testing.cfg

@@ -2,4 +2,4 @@
 --network=default-vpc
 --gcp_service_account=830293263384-compute@developer.gserviceaccount.com
 # Dev version with security support
---td_bootstrap_image=gcr.io/grpc-testing/td-grpc-bootstrap:66de7ea0e170351c9fae17232b81adbfb3e80ec3
+--td_bootstrap_image=gcr.io/trafficdirector-prod/td-grpc-bootstrap:0.10.0