Don't force assets on HTTPS -- it breaks AppCache

lib/app.rb

@@ -71,7 +71,7 @@ class App < Sinatra::Application
   configure :production do
     set :static, false
     set :docs_host, '//docs.devdocs.io'
-    set :csp, "default-src 'self' *; script-src 'self' 'unsafe-inline' https://cdn.devdocs.io https://www.google-analytics.com https://secure.gaug.es http://*.jquery.com https://*.jquery.com; font-src data:; style-src 'self' 'unsafe-inline' *; img-src 'self' * data:;"
+    set :csp, "default-src 'self' *; script-src 'self' 'unsafe-inline' http://cdn.devdocs.io https://cdn.devdocs.io https://www.google-analytics.com https://secure.gaug.es http://*.jquery.com https://*.jquery.com; font-src data:; style-src 'self' 'unsafe-inline' *; img-src 'self' * data:;"
 
     use Rack::ConditionalGet
     use Rack::ETag
@@ -91,7 +91,6 @@ class App < Sinatra::Application
     Sprockets::Helpers.configure do |config|
       config.digest = true
       config.asset_host = 'cdn.devdocs.io'
-      config.protocol = 'https://'
       config.manifest = Sprockets::Manifest.new(sprockets, assets_manifest_path)
     end
   end