Don't repeatedly call getenv in SEXP_VALIDATE
Don't repeatedly call getenv in SEXP_VALIDATE

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