IB/srp: Avoid skipping srp_reset_host() after a transport error

The SCSI error handler assumes that the transport layer is operational
if an eh_abort_handler() returns SUCCESS.  Hence srp_abort() only
should return SUCCESS if sending the ABORT TASK task management
function succeeded.  This patch avoids the SCSI error handler skipping
the srp_reset_host() call after a transport layer error.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>