fixes for 'net rpc vampire'. I can now take a blank Samba host

fixes for 'net rpc vampire'.  I can now take a blank Samba host
and migrate an NT4 domain and still logon from domain members
(tested logon scripts, system policies, profiles, & home directories)
(passdb backend = tdbsam)

removed call to idmap_init_wellknown_sids() from winbindd.c
since the local domain should be handled by the guest passdb backend
(and you don't really always want the Administrator account to be root)
...and we didn't pay attention to this anyways now.
(This used to be commit 837d7c54d3ca780160aa0d6a2f0a109bb691948e)