proxy (TLS client): remember whether or not we have seen the same server cert+SCTs
proxy (TLS client): remember whether or not we have seen the same server cert+SCTs

(and remember the validation result too)

this avoids the same child processing needlessly queueing the same backend server data
for audit over and over (think reverse proxy), as well as needless validation

trawick/ct-httpd,trawick/ct-httpd,trawick/ct-httpd,tomrittervg/ct-httpd,tomrittervg/ct-httpd,tomrittervg/ct-httpd