Fix spec that broke due to fact that iid is needed, not id, for MilestonesController

spec/controllers/projects/milestones_controller_spec.rb

@@ -5,7 +5,7 @@ describe Projects::MilestonesController do
   let(:user)    { create(:user) }
   let(:milestone) { create(:milestone, project: project) }
   let(:issue) { create(:issue, project: project, milestone: milestone) }
-  let(:merge_request) { create(:merge_request, source_project: project, target_project: project, milestone: milestone) }
+  let!(:merge_request) { create(:merge_request, source_project: project, target_project: project, milestone: milestone) }
 
   before do
     sign_in(user)
@@ -15,10 +15,9 @@ describe Projects::MilestonesController do
 
   describe "#destroy" do
     it "should remove milestone" do
-      merge_request.reload
       expect(issue.milestone_id).to eq(milestone.id)
 
-      delete :destroy, namespace_id: project.namespace.id, project_id: project.id, id: milestone.id, format: :js
+      delete :destroy, namespace_id: project.namespace.id, project_id: project.id, id: milestone.iid, format: :js
       expect(response).to be_success
 
       expect(Event.first.action).to eq(Event::DESTROYED)