Fix building of api_rest_path.
Fix building of api_rest_path.

It was building over the previous value instead of using the base one,
which caused the path to grow indefinitely until the server refused it
with a 403 error.

Fiware/tutorials.TourGuide-App,FiwareULPGC/tutorials.TourGuide-App,FiwareULPGC/tutorials.TourGuide-App,FiwareULPGC/fiware-devguide-app,Bitergia/fiware-devguide-app,FiwareULPGC/tutorials.TourGuide-App,FiwareULPGC/tutorials.TourGuide-App,FiwareULPGC/fiware-devguide-app,Fiware/tutorials.TourGuide-App,Bitergia/fiware-devguide-app,FiwareULPGC/fiware-devguide-app,Fiware/tutorials.TourGuide-App,FiwareULPGC/tutorials.TourGuide-App,FiwareULPGC/fiware-devguide-app,Bitergia/fiware-devguide-app,Fiware/tutorials.TourGuide-App,Bitergia/fiware-devguide-app,FiwareULPGC/fiware-devguide-app,Fiware/tutorials.TourGuide-App,Bitergia/fiware-devguide-app