fixes app.yaml comments for cloudsql example (GoogleCloudPlatform#475)

Author: bshaffer

appengine/standard/cloudsql/app.yaml

@@ -8,9 +8,9 @@ handlers:
 
 # [START env]
 env_variables:
-  # Replace project, instance, database, user and password with the values obtained
-  # when configuring your Cloud SQL instance.
+  # Replace USER, PASSWORD, DATABASE, and CONNECTION_NAME with the
+  # values obtained when configuring your Cloud SQL instance.
   MYSQL_DSN: mysql:unix_socket=/cloudsql/INSTANCE_CONNECTION_NAME;dbname=DATABASE
-  MYSQL_USER: root
-  MYSQL_PASSWORD: ''
+  MYSQL_USER: USER
+  MYSQL_PASSWORD: PASSWORD
 # [END env]