We have the JIRA Labels plugin bundled by default, but 'deactivated'. Due to a JIRA classloading problem, just 'activating' the plugin causes it to fail silently (AOD-1746) until JIRA is restarted (much like Greenhopper in AOD-1366). We should rather have the plugin activated by default (it's a supported plugin), and leave users to configure the custom field if they actually want it.