Installer fix for Let's Encrypt certificates.
- Installer: since 2.92.0 the check that tests whether a certificate can be issued ran
certbot --apache --dry-run, which certbot rejects with a usage error. The installer read that as "a certificate cannot be issued yet" and every new install continued over HTTP, with the fix-it hint pointing at DNS or port 80. The check now runscertbot certonly --apache --dry-run, so installs with working DNS get their certificate during setup again. Existing installs that ended up on HTTP can still runcertbot --apache -d your.hostnameonce. (#560)
No agent changes in this release.