### Please describe the problem.
This is a weird one. I'm getting rsync `protocol version mismatch -- is your shell clean?` on a particular file.

I have tried to reproduce it but not been able.

 * First time it happened, I went to the problem repo and did a `get`, which worked, destroying the evidence. "Luckily", this happened again a few days later.
 * I thought maybe it was because there was a partial transfer in `.git/annex/tmp` with some specific characteristics. Nope, if I remove the file in `tmp` the problem remains.
 * I made another clone think it was the problem repo, transferred the file to that repo, no problem. Dropped it, pointed everything back to the original bad repo. Still bad.
 * Both sides are running `rsync  version 3.1.0  protocol version 31`.


### What steps will reproduce the problem?

Working on it. But I want to put the preliminaries here, in case someone else has seen this.

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

Both sides are running `git-annex version: 5.20150508-g883d57f`, on Ubuntu 14.04.2 LTS.


### 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
$ git annex copy --to acozed claes/colt/20150511_174818.jpg 
copy claes/colt/20150511_174818.jpg (checking acozed...) (to acozed...) 
protocol version mismatch -- is your shell clean?
(see the rsync man page for an explanation)
rsync error: protocol incompatibility (code 2) at compat.c(176) [sender=3.1.1]

  rsync failed -- run git annex again to resume file transfer
failed
git-annex: copy: 1 failed


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