Skip logging for DNSSEC responses [BZ 14841]

DNSSEC defines a number of response types that one me expect when the
DO bit is set.  We don't process any of them, but since we do allow
setting the DO bit, skip them without logging an error since it is
only a nuisance.

Tested on x86_64.

	[BZ #14841]
	* resolv/gethnamaddr.c (getanswer): Skip logging if
	RES_USE_DNSSEC is set.
	* resolv/nss_dns/dns-host.c (getanswer_r): Likewise.