Factories with a project association use `:empty_project` by default

spec/factories/deploy_keys_projects.rb

 FactoryGirl.define do
   factory :deploy_keys_project do
     deploy_key
-    project
+    project factory: :empty_project
   end
 end

spec/factories/events.rb

 FactoryGirl.define do
   factory :event do
-    project
+    project factory: :empty_project
     author factory: :user
 
     factory :closed_issue_event do

spec/factories/file_uploader.rb

 FactoryGirl.define do
   factory :file_uploader do
-    project
+    project factory: :empty_project
     secret nil
 
     transient do

spec/factories/issues.rb

@@ -6,7 +6,7 @@
   factory :issue do
     title
     author
-    project
+    project factory: :empty_project
 
     trait :confidential do
       confidential true

spec/factories/labels.rb

@@ -2,7 +2,7 @@
   factory :label, class: ProjectLabel do
     sequence(:title) { |n| "label#{n}" }
     color "#990000"
-    project
+    project factory: :empty_project
 
     transient do
       priority nil

spec/factories/milestones.rb

 FactoryGirl.define do
   factory :milestone do
     title
-    project
+    project factory: :empty_project
 
     trait :active do
       state "active"

spec/factories/notes.rb

@@ -4,7 +4,7 @@
 
 FactoryGirl.define do
   factory :note do
-    project
+    project factory: :empty_project
     note "Note"
     author
     on_issue
@@ -36,6 +36,7 @@
     end
 
     factory :diff_note_on_commit, traits: [:on_commit], class: DiffNote do
+      association :project, :repository
       position do
         Gitlab::Diff::Position.new(
           old_path: "files/ruby/popen.rb",

spec/factories/project_group_links.rb

 FactoryGirl.define do
   factory :project_group_link do
-    project
+    project factory: :empty_project
     group
   end
 end

spec/factories/project_members.rb

 FactoryGirl.define do
   factory :project_member do
     user
-    project
+    project factory: :empty_project
     master
 
     trait(:guest)     { access_level ProjectMember::GUEST }

spec/factories/project_snippets.rb

 FactoryGirl.define do
   factory :project_snippet, parent: :snippet, class: :ProjectSnippet do
-    project
+    project factory: :empty_project
   end
 end

spec/factories/releases.rb

@@ -2,6 +2,6 @@
   factory :release do
     tag "v1.1.0"
     description "Awesome release"
-    project
+    project factory: :empty_project
   end
 end

spec/factories/sent_notifications.rb

 FactoryGirl.define do
   factory :sent_notification do
-    project
+    project factory: :empty_project
     recipient factory: :user
     noteable factory: :issue
     reply_key "0123456789abcdef" * 2

spec/factories/services.rb

 FactoryGirl.define do
   factory :service do
-    project
+    project factory: :empty_project
   end
 end

spec/factories/todos.rb

 FactoryGirl.define do
   factory :todo do
-    project
+    project factory: :empty_project
     author
     user
     target factory: :issue