Fix multiple printing of same error message
Fix multiple printing of same error message

See previous two commits.

Why can I do the change? Before this commit:  When oscap_source_get_scap_type returns OSCAP_DOCUMENT_UNKNOWN,
It is passed to oscap_source_get_schema_version. oscap_source_get_schema_version can return only NULL for OSCAP_DOCUMENT_UNKNOWN.
oscap_source_validate_priv returns -1 for NULL version.

Hexadorsimal/openscap,postfix/openscap,redhatrises/openscap,postfix/openscap,OpenSCAP/openscap,openprivacy/openscap,postfix/openscap,Hexadorsimal/openscap,mpreisler/openscap,postfix/openscap,Hexadorsimal/openscap,OpenSCAP/openscap,Hexadorsimal/openscap,jan-cerny/openscap,Hexadorsimal/openscap,mpreisler/openscap,ybznek/openscap,redhatrises/openscap,ybznek/openscap,openprivacy/openscap,OpenSCAP/openscap,ybznek/openscap,mpreisler/openscap,jan-cerny/openscap,postfix/openscap,ybznek/openscap,openprivacy/openscap,redhatrises/openscap,jan-cerny/openscap,openprivacy/openscap,openprivacy/openscap,ybznek/openscap,Hexadorsimal/openscap,OpenSCAP/openscap,jan-cerny/openscap,OpenSCAP/openscap,mpreisler/openscap,ybznek/openscap,jan-cerny/openscap,redhatrises/openscap,postfix/openscap,mpreisler/openscap,jan-cerny/openscap,openprivacy/openscap,redhatrises/openscap,redhatrises/openscap,mpreisler/openscap,OpenSCAP/openscap