libafs: Correct afs_LoopServers flags

libafs: Correct afs_LoopServers flags

AFS_LS_DOWN was actually checking up servers, and AFS_LS_UP was
checking down servers. Fix the handling of the 'adown' flag so we do
the right thing.

1.6-only: Note that this does not contain the change to afs_FlushVCBs,
since 1.6 does not contain change cee2c677, which introduced the
relevant afs_FlushVCBs afs_LoopServers call.

Reviewed-on: http://gerrit.openafs.org/4624
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
(cherry picked from commit 1f48bc7a30d5df88a1e5f539ee22df3952533a88)

Change-Id: Ibf56812134800a047642455a528dae488c52bcf9
Reviewed-on: http://gerrit.openafs.org/8309
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>