Update binding properties for Cloud SQL
Update binding properties for Cloud SQL

GoogleCloudPlatform/gcp-service-broker,joshlong/gcp-service-broker,rifung/gcp-service-broker,rifung/gcp-service-broker,rifung/gcp-service-broker,GoogleCloudPlatform/gcp-service-broker,joshlong/gcp-service-broker,rifung/gcp-service-broker