Merge remote-tracking branch 'upstream/master' into pipeline-notifications

* upstream/master: (221 commits)
  Differentiate the expire from leave event
  Use LabelsFinder on Fogbuz importer
  Use LabelsFinder on Google Code importer
  Change the order of tested methods in project_members_controller_spec
  Remove show_menu_above attribute from issuable dropdowns.
  Spaces before `}`!
  Avoid touch label links that does not belongs to project when moving it
  Remove order by label type on LabelsFinder
  Rename Labels::CreateService to Labels::FindOrCreateService
  Add self.project_foreign_key on both Issue and MergeRequest
  Only show label type for projects that belong to a group
  Disable subscribing to group-level labels
  Remove unused method Project#all_labels
  Update specs to cope with new label types and priorities
  Fix max number of permitted priorities per project label
  Fix GitHub importer spec
  Update CHANGELOG
  Add support to group labels to SlashCommands::InterpretService
  Use join instead of subquery on Label.unprioritized scope
  Warn user deleting a group label affect all projects within the group
  ...