convert rdata_test

- also added code to dnstest.c to optionally suppress printing of errors
  from dns_rdata_fromtxt()

lib/dns/tests/nsec3_test.c

@@ -101,7 +101,7 @@ nsec3param_salttotext_test(const nsec3param_salttotext_test_params_t *params) {
 	result = dns_test_rdatafromstring(&rdata, dns_rdataclass_in,
 					  dns_rdatatype_nsec3param, buf,
 					  sizeof(buf),
-					  params->nsec3param_text);
+					  params->nsec3param_text, false);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	result = dns_rdata_tostruct(&rdata, &nsec3param, NULL);
 	assert_int_equal(result, ISC_R_SUCCESS);