Merge pull request #1822 from mozilla/i1821-fix-oauth-keys-test r=@ianb, @vladikoff

fix(test): Fix the "fails with bad assertion" test.

packages/fxa-auth-server/fxa-oauth-server/test/api.js

@@ -3156,6 +3156,7 @@ describe('/v1', function() {
       });
 
       it('fails with bad assertion', () => {
+        mockAssertion().reply(200, VERIFY_FAILURE);
         return Server.api.post(genericRequest).then(res => {
           assert.equal(res.statusCode, 401);
           assertSecurityHeaders(res);