go.blog: simpler nobuild_files rule

R=golang-dev, dsymonds
https://golang.org/cl/13662045
diff --git a/app.yaml b/app.yaml
index 2d2d7e5..882f5c9 100644
--- a/app.yaml
+++ b/app.yaml
@@ -7,9 +7,7 @@
 - url: /favicon.ico
   static_files: static/favicon.ico
   upload: static/favicon.ico
-- url: /static
-  static_dir: static
 - url: /.*
   script: _go_app
 
-nobuild_files: ^(?!(cmd/blog|code.google.com)/)
+nobuild_files: ^(support|content)/