NOPs should not be requeued when reconnecting a session.

Just like DATA_OUT we should just discard NOPs instead of requeueing them
on session reconnect.
Add new flag that to indicate this behaviour on reconnect and set it for
both data out and nops

lib/connect.c

@@ -302,10 +302,11 @@ try_again:
 			continue;
 		}
 
-		if (pdu->flags & ISCSI_PDU_DELETE_WHEN_SENT) {
+		if (pdu->flags & ISCSI_PDU_DROP_ON_RECONNECT) {
 			/* We dont want to requeue things like DATA-OUT since these guys
 			 * will be reissued automatically anyway once the corresponding
 			 * write command is replayed.
+			 * Similarly we dont want to requeue NOPs. 
 		 	 */
 			iscsi_free_pdu(old_iscsi, pdu);
 			continue;