Don't leak context if nsi_probe failes
Don't leak context if nsi_probe failes

Deduced from valgrind log produced by Markus Moeller

madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal,madscientist159/heimdal