The findCertByIssuerFast, findCertIssuer and sk_x509_findCertByIssuer functions
does not search for a certificate with the given issuer. Actually they are
searching the certificate of the issuer of the given certificate.
This patch fixes documentation of this function and adjust the functions names:
- findCertByIssuerFast to findCertIssuerFast
- sk_x509_findCertByIssuer to sk_x509_findIssuer