### What steps will reproduce the problem?

1. Create a fresh annex repo.  Create a dummy test file and add it to the annex.
2. `git init --bare` in an empty directory on a remote machine.
3. `git initremote testremote type=gcrypt encryption=hybrid gitrepo=ssh://machine/the/remote/machine/dir keyid=my_key_id`
4. `git annex sync testremote --content`
5. Unplug network/switch off WiFi.
6. `git annex sync testremote --content`, which fails due to the broken network.
7. Reconnect network, check that can ssh to remote host.
8. `git annex sync testremote --content`

gcrypt issues warning `gcrypt: WARNING: Remote ID has changed!`

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

git-annex 5.20141125 on Debian Wheezy 32-bit.

### Please provide any additional information below.

This is essentially a gcrypt bug, so I don't know if you want to fix it, and I know that the gcrypt author is inactive.

My diagnosis is that when running `git annex sync testremote --content` when the network is disconnected, git can't SSH to the remote and gcrypt makes the mistake of regenerating the remote ID and setting up a new remote.  So when the network comes back online, the local record of the remote's gcrypt ID is just wrong.  gcrypt ought not to "set up a new repository" when there is a network failure.

    gcrypt: Development version -- Repository format MAY CHANGE
    gcrypt: Repository not found: ssh://url-here
    gcrypt: Setting up new repository
    gcrypt: Remote ID is :id:agVyn7wBG/JGwN9LW5Qn
    Counting objects: 22, done.
    Compressing objects: 100% (17/17), done.
    Total 22 (delta 4), reused 0 (delta 0)
    gcrypt: Encrypting to:  -r my_key_id_here
    gcrypt: Requesting manifest signature
    ssh: Could not resolve hostname my_remote_host_here: No such file or directory
    fatal: Could not read from remote repository.
    
    Please make sure you have the correct access rights
    and the repository exists.
    error: failed to push some refs to 'gcrypt::ssh://url-here
    
      Pushing to testremote failed.
    
      (non-fast-forward problems can be solved by setting receive.denyNonFastforwards to false in the remote's git config)
    failed
