Ensure group acts as a namespace for polymorphic routes

Signed-off-by: Rémy Coutable <remy@rymai.me>

app/views/projects/commit/_change.html.haml

@@ -13,7 +13,7 @@
         %a.close{ href: "#", "data-dismiss" => "modal" } ×
         %h3.page-title== #{label} this #{commit.change_type_title(current_user)}
       .modal-body
-        = form_tag [type.underscore, @project.namespace, @project, commit], method: :post, remote: false, class: "form-horizontal js-#{type}-form js-requires-input" do
+        = form_tag [type.underscore, @project.namespace.becomes(Namespace), @project, commit], method: :post, remote: false, class: "form-horizontal js-#{type}-form js-requires-input" do
           .form-group.branch
             = label_tag 'target_branch', target_label, class: 'control-label'
             .col-sm-10

spec/features/merge_requests/cherry_pick_spec.rb

@@ -2,7 +2,8 @@ require 'spec_helper'
 describe 'Cherry-pick Merge Requests' do
   let(:user) { create(:user) }
-  let(:project) { create(:project) }
+  let(:group) { create(:group) }
+  let(:project) { create(:project, namespace: group) }
   let(:merge_request) { create(:merge_request_with_diffs, source_project: project, author: user) }
   before do

spec/features/projects/commits/cherry_pick_spec.rb

@@ -2,7 +2,8 @@ require 'spec_helper'
 include WaitForAjax
 describe 'Cherry-pick Commits' do
-  let(:project) { create(:project) }
+  let(:group) { create(:group) }
+  let(:project) { create(:project, namespace: group) }
   let(:master_pickable_commit)  { project.commit('7d3b0f7cff5f37573aea97cebfd5692ea1689924') }
   let(:master_pickable_merge)  { project.commit('e56497bb5f03a90a51293fc6d516788730953899') }