Silence CID 329159: Logically dead code in lib/dns/journal.c

*** CID 329159:    (DEADCODE)
    /lib/dns/journal.c: 1719 in dns_journal_print()
    1713     		}
    1714     		CHECK(dns_difftuple_create(
    1715     			diff.mctx, n_soa == 1 ? DNS_DIFFOP_DEL : DNS_DIFFOP_ADD,
    1716     			name, ttl, rdata, &tuple));
    1717     		dns_diff_append(&diff, &tuple);
    1718
    >>>     CID 329159:    (DEADCODE)
    >>>     Execution cannot reach the expression "printxhdr" inside this statement: "if (++n_put != 0U || printx...".
    1719     		if (++n_put != 0 || printxhdr) {
    1720     			result = dns_diff_print(&diff, file);
    1721     			dns_diff_clear(&diff);
    1722     			n_put = 0;
    1723     			if (result != ISC_R_SUCCESS) {
    1724     				break;
    /lib/dns/journal.c: 1734 in dns_journal_print()
    1728     	if (result == ISC_R_NOMORE) {
    1729     		result = ISC_R_SUCCESS;
    1730     	}
    1731     	CHECK(result);
    1732
    1733     	if (!printxhdr && n_put != 0) {
    >>>     CID 329159:    (DEADCODE)
    >>>     Execution cannot reach this statement: "result = dns_diff_print(&di...".
    1734     		result = dns_diff_print(&diff, file);
    1735     		dns_diff_clear(&diff);
    1736     	}
    1737     	goto cleanup;
    1738
    1739     failure:

(cherry picked from commit 848e336d)

Closes #2559 (closed)