### Please describe the problem.

Adding a repository on box.com, using the assistant, fails with an error message (as seen in the log below).

### What steps will reproduce the problem?

Start up the assistant. Create a new empty repository. Enable consistency checking as suggested. Click add another repository, select box.com, fill in your credentials, keep shared ticked and encrypt all selected, click add repository. Error message appears.


### What version of git-annex are you using? On what operating system?

5.20140117.1 from ppa of François Marier

ubuntu 13.10 (saucy), i686

### Please provide any additional information below.

[[!format sh """
# If you can, paste a complete transcript of the problem occurring here.
# If the problem is with the git-annex assistant, paste in .git/annex/daemon.log

[2014-01-26 20:40:10 CET] main: starting assistant version 5.20140117.1
[2014-01-26 20:40:10 CET] Cronner: You should enable consistency checking to protect your data. 
(Recording state in git...)
(scanning...) [2014-01-26 20:40:10 CET] Watcher: Performing startup scan
(started...) [2014-01-26 20:41:10 CET] Cronner: Consistency check in progress

(Recording state in git...)
(encryption setup) (shared cipher) (testing WebDAV server...)
26/Jan/2014:20:41:24 +0100 [Error#yesod-core] InternalIOException <socket: 32>: hPutBuf: illegal operation (handle is closed) @(yesod-core-1.2.3:Yesod.Core.Class.Yesod ./Yesod/Core/Class/Yesod.hs:471:5)

# End of transcript or log.
"""]]

> Seems that [DAV-0.6 is badly broken](http://bugs.debian.org/737902).
> I have adjusted the cabal file to refuse to build with that broken
> version.
> 
>> Update: Had to work around additional breakage in DAV-0.6. It's
>> fully tested and working now, although not yet uploaded to Debian
>> unstable. [[done]] --[[Joey]]
