The 'disable cache' flag must affect on the certificate fetch request.

* https://127.0.0.1:8443/loading/sxg/resources/127.0.0.1.sxg.pem.cbor
  cached: false
* https://127.0.0.1:8443/loading/sxg/resources/127.0.0.1.sxg.pem.cbor
  cached: false
* https://127.0.0.1:8443/loading/sxg/resources/127.0.0.1.sxg.pem.cbor
  cached: true
* https://127.0.0.1:8443/loading/sxg/resources/127.0.0.1.sxg.pem.cbor
  cached: false