require_oauth decorator was always succeeding.

verify_request() returns a tuple of (valid, oauth_request). The code was
treating it as if it returned just a bool, and since the never-empty
tuple was always truthy, requests always seemed to work.

Fixes ib-lundgren/flask-oauthprovider/ib-lundgren#3

flask_oauthprovider.py

@@ -275,14 +275,15 @@ def verify_request(*args, **kwargs):
                         body = request.form.to_dict()
                     else:
                         body = request.data.decode("utf-8")
-                    valid = self.verify_request(request.url.decode("utf-8"),
+                    verify_result = self.verify_request(request.url.decode("utf-8"),
                             http_method=request.method.decode("utf-8"),
                             body=body,
                             headers=request.headers,
                             require_resource_owner=require_resource_owner,
                             require_verifier=require_verifier,
                             require_realm=require_realm or bool(realm),
                             required_realm=realm)
+                    valid, oauth_request = verify_result
                     if valid:
                         request.oauth = self.collect_request_parameters(request)