Removed /api from dispatch

I had that in there to test it out (for the comments above) but I don't
want that to be in the main example, so I'm removing it. Also, it needs
to be consistent with the curl/ab requests that are/might-be mentioned
in the recipe.

embed/event-machine.md

@@ -54,7 +54,7 @@ def run
     #     /api/hello
     #     /api/goodbye
     dispatch = Rack::Builder.app do
-      map '/api' do
+      map '/' do
         run web_app
       end
     end