Allow to delete answers if the poll has not started yet

Deleting answers was not even possible. But it was possible to delete
questions. So we implemented the same behavior.

spec/controllers/admin/poll/questions/answers_controller_spec.rb

@@ -85,4 +85,23 @@ describe Admin::Poll::Questions::AnswersController, :admin do
       expect(future_answer.reload.title).to eq "New title"
     end
   end
+
+  describe "DELETE destroy" do
+    it "is not possible for an already started poll" do
+      current_answer = create(:poll_question_answer, question: current_question)
+      delete :destroy, params: { question_id: current_question, id: current_answer }
+
+      expect(flash[:alert]).to eq "You do not have permission to carry out the action 'destroy' on Answer."
+      expect(Poll::Question::Answer.count).to eq 1
+    end
+
+    it "is possible for a not started poll" do
+      future_answer = create(:poll_question_answer, question: future_question)
+      delete :destroy, params: { question_id: future_question, id: future_answer }
+
+      expect(response).to redirect_to admin_question_path(future_question)
+      expect(flash[:notice]).to eq "Answer deleted successfully"
+      expect(Poll::Question::Answer.count).to eq 0
+    end
+  end
 end