The linux.vnet.ibm.com domain will be discontinued end of 2018.
Instead the new linux.ibm.com domain is already active.

Reflect this by changing the email addresses of maintainers active in
the s390 area accordingly.
Acked-by: NBenjamin Block <bblock@linux.ibm.com>
Acked-by: NDong Jia Shi <bjsdjshi@linux.ibm.com>
Acked-by: NHalil Pasic <pasic@linux.ibm.com>
Acked-by: NJan Hoeppner <hoeppner@linux.ibm.com>
Acked-by: NJanosch Frank <frankja@linux.ibm.com>
Acked-by: NJulian Wiedmann <jwi@linux.ibm.com>
Acked-by: NPeter Oberparleiter <oberpar@linux.ibm.com>
Acked-by: NSebastian Ott <sebott@linux.ibm.com>
Acked-by: NStefan Haberland <sth@linux.ibm.com>
Acked-by: NSteffen Maier <maier@linux.ibm.com>
Acked-by: NUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>