Fix sslcrtd and external_acl helper name lifetimes (#843)

Fix sslcrtd and external_acl helper name lifetimes (#843)

    helperShutdown: <binary garbage> #Hlpr523 shutting down.
    helperShutdown: See example.net/legal-terms #Hlpr4456 shutting down.

Busy "class helper" objects often outlive configuration that was used to
create them. Ideally, the supplied helper category name should be copied
and maintained by the helper object itself, but that long-term solution
requires a lot more work (TODO) due to out-of-scope bugs.