fileserver: dropbox mode shouldn't allow readback from anonymous
if you're writing files as anonymous, don't let them be read back.
things which potentially need to page back in will just have to be
authenticated, or lose.
Change-Id: I71a6096239eb59b40a9df09460e8db160e9342da
Reviewed-on: http://gerrit.openafs.org/3901
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>