Improvements to App Engine Standard Wordpress README (GoogleCloudPlatform#440)

Author: ryanmats

appengine/wordpress/README.md

@@ -11,15 +11,13 @@ working WordPress project for
 * Install [Composer][composer]
 * Create a new Cloud Project on [Developers Console][dev-console]
 * Enable Billing on that project
+* [Enable Cloud SQL API][cloud-sql-api-enable] (For App Engine flexible environment)
 * Create App Engine default bucket at [App Engine Setting Page][app-engine-setting]
 * Install [Google Cloud SDK][gcloud-sdk]
 
-## Prerequisites for standard environment
+## Prerequisites for standard environment only
 * Install mysql
 
-## Prerequisites for flexible environment
-* [Enable Cloud SQL API][cloud-sql-api-enable] (For App Engine flexible environment)
-
 ## Project preparation
 
 Configure Google Cloud SDK with your account and the Project.