Log Message:
Remove unnecessary RCD_SCRIPT_WRK.<script> definitions.

RCD_SCRIPT_WRK.<script> was set previously to prevent a name conflict
with ${WRKSRC} because in the past, it defaulted to ${WRKDIR}/<script>.
This has since been changed to default to ${WRKDIR}/.rc.d/<script> to
prevent unintended name collisions, which makes this definition no longer
needed.