Calling Charts in the Repository menu of a project produces 503 error

In production.log you will find:

Started GET "/.../graphs/master/charts" for xxx.xxx.xxx.xxx at 2018-04-25 11:00:44 +0200
Processing by Projects::GraphsController#charts as HTML
  Parameters: {"namespace_id"=>"...", "project_id"=>"...", "id"=>"master"}

Gitlab::Git::CommandError (2:invalid character 'b' looking for beginning of value):
  lib/gitlab/git/repository.rb:1370:in `rescue in gitaly_migrate'
  lib/gitlab/git/repository.rb:1363:in `gitaly_migrate'
  lib/gitlab/git/repository.rb:1014:in `languages'
  app/models/repository.rb:450:in `method_missing'
  app/controllers/projects/graphs_controller.rb:46:in `get_languages'
  app/controllers/projects/graphs_controller.rb:28:in `charts'
  lib/gitlab/i18n.rb:50:in `with_locale'
  lib/gitlab/i18n.rb:56:in `with_user_locale'
  app/controllers/application_controller.rb:330:in `set_locale'
  lib/gitlab/middleware/multipart.rb:95:in `call'
  lib/gitlab/request_profiler/middleware.rb:14:in `call'
  lib/gitlab/middleware/go.rb:17:in `call'
  lib/gitlab/etag_caching/middleware.rb:11:in `call'
  lib/gitlab/middleware/read_only/controller.rb:28:in `call'
  lib/gitlab/middleware/read_only.rb:16:in `call'
  lib/gitlab/request_context.rb:18:in `call'
  lib/gitlab/metrics/requests_rack_middleware.rb:27:in `call'
  lib/gitlab/middleware/release_env.rb:10:in `call'

Completed 503 Service Unavailable in 626ms (Views: 47.5ms | ActiveRecord: 8.5ms)

Your gitlab here at https://gitlab.awesome-it.de/ is also affected.

This is caused by the binaries in /var/lib/gitlab-gitaly/ruby/vendor/bundle/ruby/2.3.0/bin not being executable. In the source Git-Repo at https://gitlab.com/gitlab-org/gitaly.git they are executable but the doins -r "ruby" in the ebuild removes the x-bit.

I fixed this by the attached patch.gitlab-gitaly.patch