Add missing trait and remove spec that doesn't make sense in this branch

The `repository_access_level` attribute doesn't exist in the 8-12-stable
branch so repository access cannot be restricted using this feature.

Fortunately we use `can?(user, :download_code, ref_project)` in
lib/banzai/reference_parser/commit_parser.rb and
lib/banzai/reference_parser/commit_range_parser.rb and this permission
already exists in 8-12-stable (it only depends on the project
`visibility_access`).
Signed-off-by: Rémy Coutable <remy@rymai.me>

spec/factories/group_members.rb

@@ -3,5 +3,11 @@ FactoryGirl.define do
     access_level { GroupMember::OWNER }
     group
     user
+
+    trait(:guest)     { access_level GroupMember::GUEST }
+    trait(:reporter)  { access_level GroupMember::REPORTER }
+    trait(:developer) { access_level GroupMember::DEVELOPER }
+    trait(:master)    { access_level GroupMember::MASTER }
+    trait(:owner)     { access_level GroupMember::OWNER }
   end
 end

spec/lib/banzai/reference_parser/commit_parser_spec.rb

@@ -8,14 +8,6 @@ describe Banzai::ReferenceParser::CommitParser, lib: true do
   subject { described_class.new(project, user) }
   let(:link) { empty_html_link }
 
-  describe '#nodes_visible_to_user' do
-    context 'when the link has a data-issue attribute' do
-      before { link['data-commit'] = 123 }
-
-      it_behaves_like "referenced feature visibility", "repository"
-    end
-  end
-
   describe '#referenced_by' do
     context 'when the link has a data-project attribute' do
       before do

spec/lib/banzai/reference_parser/commit_range_parser_spec.rb

@@ -8,14 +8,6 @@ describe Banzai::ReferenceParser::CommitRangeParser, lib: true do
   subject { described_class.new(project, user) }
   let(:link) { empty_html_link }
 
-  describe '#nodes_visible_to_user' do
-    context 'when the link has a data-issue attribute' do
-      before { link['data-commit-range'] = '123..456' }
-
-      it_behaves_like "referenced feature visibility", "repository"
-    end
-  end
-
   describe '#referenced_by' do
     context 'when the link has a data-project attribute' do
       before do