Update mock and stub syntax for specs

app/helpers/broadcast_messages_helper.rb

app/helpers/icons_helper.rb

app/helpers/notifications_helper.rb

spec/controllers/autocomplete_controller_spec.rb

spec/features/gitlab_flavored_markdown_spec.rb

spec/features/profile_spec.rb

spec/helpers/application_helper_spec.rb

spec/helpers/broadcast_messages_helper_spec.rb

spec/helpers/diff_helper_spec.rb

spec/helpers/notifications_helper_spec.rb

spec/helpers/submodule_helper_spec.rb

spec/lib/extracts_path_spec.rb

spec/lib/gitlab/auth_spec.rb

spec/lib/gitlab/backend/shell_spec.rb

spec/lib/gitlab/ldap/access_spec.rb

spec/lib/gitlab/ldap/adapter_spec.rb

spec/lib/gitlab/ldap/authentication_spec.rb

spec/lib/gitlab/ldap/user_spec.rb

spec/lib/gitlab/upgrader_spec.rb

spec/models/commit_spec.rb