Ensure the PKCS-7 client certificate exists at startup
Ensure the PKCS-7 client certificate exists at startup

This ensures the certificate is always present even before the user has
generated a report or manually signed test data.

Also, if the GnuTLS version is too old just log a message and continue.

hughsie/fwupd,fwupd/fwupd,vathpela/fwupd,hughsie/fwupd,fwupd/fwupd,vathpela/fwupd,hughsie/fwupd,vathpela/fwupd,fwupd/fwupd,fwupd/fwupd,vathpela/fwupd,hughsie/fwupd