getting-started/bookshelf: comment out cloud_sql_instances by default
The app won't deploy with an invalid instance string.
@@ -13,5 +13,5 @@ env_variables:
#
# This should match the value in config.go
beta_settings:
- cloud_sql_instances: INSTANCE_CONNECTION_NAME
+# cloud_sql_instances: INSTANCE_CONNECTION_NAME
# [END cloudsql_settings]
