clean up outdated code

src/flask/app.py

@@ -23,7 +23,6 @@ from werkzeug.exceptions import BadRequestKeyError
 from werkzeug.exceptions import default_exceptions
 from werkzeug.exceptions import HTTPException
 from werkzeug.exceptions import InternalServerError
-from werkzeug.exceptions import MethodNotAllowed
 from werkzeug.routing import BuildError
 from werkzeug.routing import Map
 from werkzeug.routing import RequestRedirect
@@ -2000,17 +1999,7 @@ class Flask(_PackageBoundObject):
         .. versionadded:: 0.7
         """
         adapter = _request_ctx_stack.top.url_adapter
-        if hasattr(adapter, "allowed_methods"):
-            methods = adapter.allowed_methods()
-        else:
-            # fallback for Werkzeug < 0.7
-            methods = []
-            try:
-                adapter.match(method="--")
-            except MethodNotAllowed as e:
-                methods = e.valid_methods
-            except HTTPException:
-                pass
+        methods = adapter.allowed_methods()
         rv = self.response_class()
         rv.allow.update(methods)
         return rv