ConfigDirectory overloads ConfigFile's load but it should be load2.

Discovered when preparing Jenkins 2.319 and 2.303.3, the submission of directory rules through the UI wipes the default rules bundled with Jenkins until restart.

See first INFO block in https://www.jenkins.io/doc/upgrade-guide/2.303/#SECURITY-2455

This is a regression in 2.111, https://github.com/jenkinsci/jenkins/pull/3211