Added some minimal debugging for transmitted PDUs.

src/net/tcp/iscsi.c

 	command->cmdsn = htonl ( iscsi->cmdsn );
 	command->expstatsn = htonl ( iscsi->statsn + 1 );
 	memcpy ( &command->cdb, &iscsi->command->cdb, sizeof ( command->cdb ));
+	DBG ( "iSCSI %p start " SCSI_CDB_FORMAT " %s %#x\n",
+	      iscsi, SCSI_CDB_DATA ( command->cdb ),
+	      ( iscsi->command->data_in ? "in" : "out" ),
+	      ( iscsi->command->data_in ?
+		iscsi->command->data_in_len : iscsi->command->data_out_len ) );
 }
 
 /**
 	data_out->expstatsn = htonl ( iscsi->statsn + 1 );
 	data_out->datasn = htonl ( datasn );
 	data_out->offset = htonl ( iscsi->transfer_offset + offset );
+	DBG ( "iSCSI %p start data out DataSN %#x len %#lx\n",
+	      iscsi, datasn, len );
 }
 
 /**