+PP/14 Fix OCSP reinitialisation in SNI handling for Exim/TLS as server.
+ Bug spotted by Jeremy Harris; was flawed since initial commit.
+ Would have resulted in OCSP responses post-SNI triggering an Exim
+ NULL dereference and crash.
+
+JH/13 Add $router_name and $transport_name variables. Bugzilla 308.
+