[S390] dasd: Use default recovery for SNSS requests

[S390] dasd: Use default recovery for SNSS requests

For extended error reporting we sometimes have to start an
Sense Subsystem Status request (SNSS). When this request needs
to be recovered for some reason, the recovery request will
fail with 'command reject'.
Our usual recovery procedure will retry the failed request by
creating a new request and chaining the failed request from that
one. SNSS requests, though, must not be chained from anything,
so the recovery request will fail permanently.
Use the default recovery for SNSS request, which will just restart
the original request without further ado.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>