Silence REVERSE_INULL

Silence REVERSE_INULL

Remove unnecessary != NULL checks

    *** CID 352809:  Null pointer dereferences  (REVERSE_INULL) /lib/dns/message.c: 4654 in dns_message_buildopt()
    4648     	if (rdata != NULL) {
    4649     		dns_message_puttemprdata(message, &rdata);
    4650     	}
    4651     	if (rdataset != NULL) {
    4652     		dns_message_puttemprdataset(message, &rdataset);
    4653     	}
    >>>     CID 352809:  Null pointer dereferences  (REVERSE_INULL)
    >>>     Null-checking "rdatalist" suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
    4654     	if (rdatalist != NULL) {
    4655     		dns_message_puttemprdatalist(message, &rdatalist);
    4656     	}
    4657     	return (result);
    4658     }
    4659