Comment 5 for bug 608314

Confirmed fixed for Lucid with the package in lucid-proposed. The "lo" interface is not displayed:

(...)
  System information as of Fri Aug 20 14:28:00 UTC 2010

  System load: 0.29 Processes: 86
  Usage of /: 57.1% of 1.36GB Users logged in: 0
  Memory usage: 36% IP address for eth0: 172.56.125.35
  Swap usage: 0%
(...)

The interface exists:
ubuntu@ip-172-56-125-35:~$ ifconfig lo
lo Link encap:Local Loopback
          inet addr:127.0.0.1 Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING MTU:16436 Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

The package comes from lucid-proposed:
ubuntu@ip-172-56-125-35:~$ apt-cache policy landscape-client
landscape-client:
  Installed: 1.5.4-0ubuntu0.10.04.0
  Candidate: 1.5.4-0ubuntu0.10.04.0
  Version table:
 *** 1.5.4-0ubuntu0.10.04.0 0
        500 http://archive.ubuntu.com/ubuntu/ lucid-proposed/main Packages
        100 /var/lib/dpkg/status
     1.5.2.1-0ubuntu0.10.04.0 0
        500 http://archive.ubuntu.com/ubuntu/ lucid-updates/main Packages
     1.5.0.1-0ubuntu0.10.04.0 0
        500 http://archive.ubuntu.com/ubuntu/ lucid/main Packages
ubuntu@ip-172-56-125-35:~$