Run git-lfs-authenticate script with original command line arguments

CHANGELOG

+v2.6.5 (unreleased)
+  - Add git-lfs-authenticate command to white list (this command is used by git-lfs for SSO authentication through SSH-protocol)
+
 v2.6.4
   - Remove keys from authorized_keys in-place
   - Increase batch_add_keys lock timeout to 300 seconds

lib/gitlab_shell.rb

@@ -111,6 +111,8 @@ class GitlabShell
 
       $logger.info "gitlab-shell: executing git-annex command <#{parsed_args.join(' ')}> for #{log_username}."
       exec_cmd(*parsed_args)
+    elsif @git_cmd == 'git-lfs-authenticate'
+      exec_cmd(@origin_cmd)
     else
       $logger.info "gitlab-shell: executing git command <#{@git_cmd} #{repo_full_path}> for #{log_username}."
       exec_cmd(@git_cmd, repo_full_path)