viced: Ignore client loopback alternate addresses

When we receive interface information from a client to determine its
alternate IP addresses, ignore any addresses that look like loopback.

Reviewed-on: http://gerrit.openafs.org/2368
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Reviewed-by: Alistair Ferguson <alistair.ferguson@mac.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>
(cherry picked from commit 2a6ddae62e4fac5eecdf4634746e7294405393d6)

Change-Id: Idcdaabd3aad62f0e84efbaf1d8523338bc683924
Reviewed-on: http://gerrit.openafs.org/9466
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Tested-by: BuildBot <buildbot@rampaginggeek.com>