Hash#slice doesn't exist in Ruby 2.1
I discovered while trying to find the build failures introduced by !6879 (merged) that Hash#slice
doesn't exist in Ruby 2.1!
It's surprising we don't have more spec failures in Ruby 2.1 due to this:
app/controllers/projects/wikis_controller.rb: params[:wiki].slice(:title, :content, :format, :message)
app/helpers/notes_helper.rb: @comments_target.slice(:noteable_id, :noteable_type, :commit_id)
app/models/concerns/issuable.rb: repository: project.hook_attrs.slice(:name, :url, :description, :homepage)
app/models/merge_request_diff.rb: # new_attributes[:st_commits].first.slice(:committed_date)
app/models/merge_request_diff.rb: # YAML.load(YAML.dump(new_attributes[:st_commits].first.slice(:committed_date)))
app/services/labels/transfer_service.rb: params = label.attributes.slice('title', 'description', 'color')
app/services/todo_service.rb: user.todos.pending.where(criteria.slice(*valid_keys))
lib/api/entities.rb: service.properties.slice(*field_names)
lib/banzai/filter/abstract_reference_filter.rb: project_refs_cache.slice(*paths).values
lib/gitlab/data_builder/note.rb: repository: project.hook_attrs.slice(:name, :url, :description, :homepage)
lib/gitlab/data_builder/push.rb: repository: project.hook_attrs.slice(:name, :url, :description, :homepage,
lib/gitlab/import_export/relation_factory.rb: finder_hash = parsed_relation_hash.slice(*finder_attributes)