Convert OVAL schema version to SEXP
Convert OVAL schema version to SEXP

This pass to the probe schema version of specific platform extension.
This commit changes communication protocol between oscap and probes.
Before, the version was encoded as an 32 bit integer,
now, it is a string.

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