metapakage should include nscd

[Nick Fenger]

nscd is critical to prevent the LDAP server from running out of file handles in a larger environment which causes clients to lock up solid. It also speeds things up dramatically on the client because it caches directory information locally preventing network round trip delays. We just saw a significant performance improvement using it and I do not see this mentioned very often in the Ubuntu LDAP documentation. It does not appear to be installed by default on UbuntuLTSP where it is critical when LDAP is enabled.