[probes] probe API: fix probe_obj_attrexists to search for non-valued attributes
[probes] probe API: fix probe_obj_attrexists to search for non-valued attributes

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