storage/appengine: fix YAML syntax

Change-Id: Ib29820f8574a3ba09fce8079f75b933011ef2cee
Reviewed-on: https://go-review.googlesource.com/35267Reviewed-by: Russ Cox <rsc@golang.org>

storage/appengine/app.yaml

@@ -16,9 +16,9 @@ handlers:
   script: _go_app
   secure: always
 env_variables:
-  CLOUDSQL_CONNECTION_NAME: golang-org:us-central1:golang-org
-  CLOUDSQL_USER: root
-  CLOUDSQL_PASSWORD: ''
-  CLOUDSQL_DATABASE: perfdata
-  GCS_BUCKET: golang-perfdata
-  PERFDATA_VIEW_URL_BASE: https://perf.golang.org/search?q=uploadid:
+  CLOUDSQL_CONNECTION_NAME: "golang-org:us-central1:golang-org"
+  CLOUDSQL_USER: "root"
+  CLOUDSQL_PASSWORD: ""
+  CLOUDSQL_DATABASE: "perfdata"
+  GCS_BUCKET: "golang-perfdata"
+  PERFDATA_VIEW_URL_BASE: "https://perf.golang.org/search?q=uploadid:"