Revert "wsgi: "method" is a required key of any "path_entry"."

Except it is not present on caucase root object.
This reverts commit b26eeb38.

caucase/wsgi.py

@@ -254,7 +254,10 @@ class Application(object):
           except KeyError:
             break
           del path_item_list[0]
-        method_dict = path_entry_dict['method']
+        try:
+          method_dict = path_entry_dict['method']
+        except KeyError:
+          raise NotFound
         request_method = environ['REQUEST_METHOD']
         try:
           action_dict = method_dict[request_method]