Have raketask tell gitaly where to find shell

lib/tasks/gitlab/gitaly.rake

@@ -66,6 +66,7 @@ namespace :gitlab do
       config = { socket_path: address.sub(%r{\Aunix:}, ''), storage: storages }
       config[:auth] = { token: 'secret' } if Rails.env.test?
       config[:'gitaly-ruby'] = { dir: File.join(Dir.pwd, 'ruby') } if gitaly_ruby
+      config[:'gitlab-shell'] = { dir: Gitlab.config.gitlab_shell.path }
       TOML.dump(config)
     end