MINOR: ssl: add a new function ssl_sock_get_ssl_object()

This one can be used later to get a SSL object from connection. It will
return NULL if connection is not established over SSL.
diff --git a/include/proto/ssl_sock.h b/include/proto/ssl_sock.h
index d029394..0751f70 100644
--- a/include/proto/ssl_sock.h
+++ b/include/proto/ssl_sock.h
@@ -109,6 +109,8 @@
  */
 int ssl_sock_register_msg_callback(ssl_sock_msg_callback_func func);
 
+SSL *ssl_sock_get_ssl_object(struct connection *conn);
+
 #endif /* USE_OPENSSL */
 #endif /* _PROTO_SSL_SOCK_H */