Complete removal of DUX client code

Complete removal of DUX client code

With commit cfce015ead18c72ee921f480c73e9247a98838fc (in 2006) all
of the files specific to the DUX cache manager were removed.
However, the DUX code within general files remained untouched.
This patch completes the removal of the (entirely non-functional)
DUX client, by removing all cache manager code which is for
AFS_DUX*_ENV and AFS_OSF_ENV platforms.

It also takes the advantage of this removal to simplify some #ifdef
ladders, and indents others (purely because I needed the indentation
to work out what on earth was going on!)

Change-Id: Icbea5ed3ef94c5e902cdb0d722be85f376c3d296
Reviewed-on: http://gerrit.openafs.org/785
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>