Windows: Dfs Referrals Processing. Not all errors are errors.

Windows: Dfs Referrals Processing.  Not all errors are errors.

When processing a Dfs Referral request, not all lookup errors
should be treated as if the path does not exist.  Servers being
down or busy, volumes offline, cell vldb servers not found, etc.
do not mean that the client should go searching elsewhere to
evaluate the path.

LICENSE MIT

Reviewed-on: http://gerrit.openafs.org/304
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>