ITS#9156 - Remove ppolicy.schema from README

Also remove nadf.schema, that got removed some time long ago

servers/slapd/schema/README

@@ -12,10 +12,8 @@ dyngroup.schema			Dynamic Group (experimental)
 inetorgperson.schema    InetOrgPerson
 java.schema             Java Object
 misc.schema             Miscellaneous Schema (experimental)
-nadf.schema             North American Directory Forum (obsolete)
 nis.schema              Network Information Service (experimental)
 openldap.schema         OpenLDAP Project (FYI)
-ppolicy.schema          Password Policy Schema (work in progress)
 
 Additional "generally useful" schema definitions can be submitted
 using the OpenLDAP Issue Tracking System <http://www.openldap.org/its/>.