s3: libgpo: Allow skipping GPO objects that don't have the expected LDAP attributes.

s3: libgpo: Allow skipping GPO objects that don't have the expected LDAP attributes.

We expect the following attributes to be present in an LDAP GPO object:

displayName
flags
gPCFileSysPath
name
ntSecurityDescriptor
versionNumber

and fail if a result is returned without them. Change this
to skip results that don't contain these attributes instead.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12695

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Guenther Deschner <gd@samba.org>