IB/srpt: Fix how aborted commands are processed

srpt_abort_cmd() must not be called in state SRPT_STATE_DATA_IN. Issue
a warning if this occurs.

srpt_abort_cmd() must not invoke target_put_sess_cmd() for commands
in state SRPT_STATE_DONE because the srpt_abort_cmd() callers already
do this when necessary. Hence remove this call.

If an RDMA read fails the corresponding SCSI command must fail. Hence
add a transport_generic_request_failure() call.

Remove an incorrect srpt_abort_cmd() call from srpt_rdma_write_done().

Avoid that srpt_send_done() calls srpt_abort_cmd() for finished SCSI
commands.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Estrin <alex.estrin@intel.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>