MINOR: haterm: add note about QUIC usage on SSL port

Update the usage message to clarify that QUIC is automatically enabled
on the SSL port when supported by the build.

Should be backported to 3.4.

src/haterm_init.c

@@ -34,6 +34,7 @@ static void haterm_usage(char *name)
 		"        --" QUIC_BIND_LONG_OPT " <opts> : append options to QUIC \"bind\" lines\n"
 #endif
 		"        --" TCP_BIND_LONG_OPT " <opts> : append options to TCP \"bind\" lines\n"
+		"Note: QUIC is automatically enabled on the SSL port if built in.\n"
 		, name);
 	exit(1);
 }