Code review comment for ~ahasenack/ubuntu/+source/libnfsidmap:bionic-uid-map-krb5-1819197

I did a codesearch in debian (https://codesearch.debian.net/search?q=nfs4_gss_princ_to_ids) for nfs4_gss_princ_to_ids, and the only non-libnfsidmap package that calls it is nfs-utils. Doesn't tell me yet if that function always uses a well formatted principal name.