[OVAL] resolve several compiler warnings
[OVAL] resolve several compiler warnings

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