Remove controllers spec already tested elsewhere

spec/features/sounds/crud_spec.rb

@@ -0,0 +1,16 @@
+feature 'Sounds CRUD' do
+  include AcceptanceHelpers
+
+  background { sign_in }
+
+  scenario 'shows sound' do
+    track = create_track file: true
+    visit tracks_path
+    click_link track[:name]
+
+    visit find('audio')[:src]
+
+    expect(response_headers['Content-Type']).to eq 'audio/mpeg'
+    expect(page.body).to eq File.read(track[:file].path, mode: 'rb')
+  end
+end