Fixes a copy&paste error
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2568)
Additionally B<XKU_SGC> is set if either Netscape or Microsoft SGC OIDs are
present.
-X509_get_extended_key_usage() return an internal pointer to the subject key
+X509_get0_subject_key_id() returns an internal pointer to the subject key
identifier of B<x> as an B<ASN1_OCTET_STRING> or B<NULL> if the extension
is not present or cannot be parsed.