Use just "free" instead of "oscap_free" in SCE
Use just "free" instead of "oscap_free" in SCE

Makes it less confusing for new contributors and oscap_free doesn't
really do anything except call free.

Also removed a bunch of if not NULL free, it's not necessary and is just
dummy code.

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