Reset DBG_AGENT first as before (#274)
Reset DBG_AGENT first as before (#274)

* Disable Stackdriver Debugger when running locally

* Start with empty DBG_ENABLE

GoogleCloudPlatform/openjdk-runtime,GoogleCloudPlatform/openjdk-runtime,GoogleCloudPlatform/jetty-runtime,GoogleCloudPlatform/jetty-runtime,GoogleCloudPlatform/jetty-runtime,GoogleCloudPlatform/jetty-runtime,GoogleCloudPlatform/openjdk-runtime