MINOR: config: Option --transparent can be set via configuration file

This patch allows to set option --transparent in an SSLH configuration
file. Without it, transparent mode is only possible by passing the
option on the command line.

example.cfg

@@ -7,6 +7,7 @@ verbose: true;
 foreground: true;
 inetd: false;
 numeric: false;
+transparent: false;
 timeout: 2;
 user: "nobody";
 pidfile: "/var/run/sslh.pid";