Use OSCAP_GSYM to get offline mode in system info probe
Use OSCAP_GSYM to get offline mode in system info probe

This is consistent with how other probes are using it.
It is the only place where this option was get.

mpreisler/openscap,jan-cerny/openscap,mpreisler/openscap,redhatrises/openscap,jan-cerny/openscap,redhatrises/openscap,redhatrises/openscap,jan-cerny/openscap,jan-cerny/openscap,redhatrises/openscap,jan-cerny/openscap,mpreisler/openscap,OpenSCAP/openscap,mpreisler/openscap,redhatrises/openscap,OpenSCAP/openscap,mpreisler/openscap,OpenSCAP/openscap,OpenSCAP/openscap,redhatrises/openscap,mpreisler/openscap,jan-cerny/openscap,OpenSCAP/openscap,OpenSCAP/openscap