fix RT#126

see https://lists.fedorahosted.org/archives/list/sssd-users@lists.fedorahosted.org/thread/YHHYVVTUEFFR5MY5P7B4Q2WX2R5GVFVX/

ad-auth/templates/sssd.conf.j2

@@ -26,3 +26,5 @@ krb5_lifetime = 48h
 krb5_renewable_lifetime = 200h
 krb5_renew_interval = 30m
 ad_gpo_access_control = disabled
+ldap_search_base = dc=fsmpi,dc=rwth-aachen,dc=de?subtree?(&(!(objectClass=computer))(!(userAccountControl:1.2.840.113556.1.4.803:=2)))
+