The virIdentity getters are unusual in that they return -1 to indicate
"not found" and don't report any error. Change them to return -1 for
real errors, 0 for not found, and 1 for success.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>