Fix teaspoon spec.

- We added a `current_user.two_factor_via_otp?` check to the view. When
  rendering the view via the teaspoon fixture, `current_user` is `nil`.

spec/javascripts/fixtures/u2f/register.html.haml

-= render partial: "u2f/register", locals: { create_u2f_profile_two_factor_auth_path: '/profile/two_factor_auth/create_u2f' }
+- user = FactoryGirl.build(:user, :two_factor_via_otp)
+= render partial: "u2f/register", locals: { create_u2f_profile_two_factor_auth_path: '/profile/two_factor_auth/create_u2f', current_user: user }