as raised in#3634 - RFC 5280 states that the issuer field cannot be
empty, but this could easily happen with selfsigned certs which had
an empty subject (as the issuer matches the subject when the cert is
self signed)
this commit detects when a cert would be issued selfsigned with an
empty subject DN and emits a warning event, allowing cluster operators
to detect the warning and potentially either re-issue to generate a
compliant cert, or else accept the risk.
Signed-off-by: Ashley Davis <ashley.davis@jetstack.io>
5e31fa37ff