If we exit due to AddressSanitizer error, we remain in raw mode, which
is not best user experience. Currently every exit is an AddressSanitizer
death due to leaks. We want to encourage users to always have ASan
enabled, to catch more errors, thus call cookmode() on exit.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>