[S390] vmlogrdr: stop IUCV connection in vmlogrdr_release.

Reopen of /dev/account failed. The IUCV path has to be terminated
in vmlogrdr_release.

Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>