[SCSI] zfcp: no port recovery after ADISC request timeout

A remote port remains in error state even if we receive a RSCN
stating that the connection is re-established. The port recovery
is not started due to a flag which is not reset.
The solution is to clear the flag in question before we trigger a ERP.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>