If our (fake) metadata server provides a 404 instead of a JSON document,
the NSS module segfaults, and as we do NSS lookups through ns(n)cd,
not only crashes the application doing the NSS lookup, but our ns(n)cd.
This has been causing segfaults of nscd all along, but since our switch
from glibc-nscd to nsncd, caused the test to fail entirely.
In any case, by handling /computeMetadata/v1/oslogin/groups we get the
NSS lookup to not cause any segfaults, and to succeed the test again.
