+PP/01 Fix default prime selection to be consistent.
+ One path used ike23 still, instead of exim.dev.20160529.3; now both
+ execution flows will use the same DH primes (currently
+ exim.dev.20160529.3).
+
+JH/25 OpenSSL: Fix back-compatibiility behaviour surrounding tls_certificates
+ option in smtp transport, to match the documentation. Previously
+ verification was not being done in some cases where it should have been.
+