finale: Tidy header includes

finale: Tidy header includes

Since we adopted libroken, we get a lot of header includes automatically
from roken.h. Use these, instead of including lots of things multiple
times.

Also, tidy up translate_et_nt.c by removing the AIX specific code which
will never be built, as this file is only compiled on Windows!

Change-Id: Iec7a811f02eaf1a2ad573bbadc30d782426231d0
Reviewed-on: http://gerrit.openafs.org/4327
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>