s390/3270: hangup the 3270 tty after a disconnect

The disconnect and later reconnect of a 3270 terminal does not do
a tty hangup. The current session is resumed which is a security
issue.

Do a tty hangup after a unit check has been received.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
1 file changed