Capture failures from krb5_cc_get_principal()
Capture failures from krb5_cc_get_principal()

Reported by Guillaume Rousse

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