Remove duplicit "oscap_strdup" from "oval_message_clone" function.
Remove duplicit "oscap_strdup" from "oval_message_clone" function.

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