### Please describe the problem.
Internal Server Error when setting up new annex and git push.default set to simple.

### What steps will reproduce the problem?
git v1.8.2.1 installed on mac os x 10.8.3 via brew

Set push.default = simple (for 2.0-style push handling)
Point git-annex-assistant at a directory.

### What version of git-annex are you using? On what operating system?
git-annex version 4.20130422-gb9341fd (from annex-assistant's footer)
git version 1.8.2.1
Mac OS X 10.8.3

### Please provide any additional information below.

Changing the push.default to "matching" 

The error message as shown was:

Internal Server Error
git init failed!
Output:
error: Malformed value for push.default: simple
error: Must be one of nothing, matching, tracking or current.
fatal: bad config file line 22 in /Users/nhyde/.gitconfig

My .gitconfig is as follows:

[user]
    email = nhyde@example.com
    #email =  
    name = Nathan Hyde
[alias]
    st = status
    ci = commit
    br = branch
    co = checkout
    df = diff
    lg = log -p
    who = shortlog -s --
    fs = flow feature start
    ff = flow feature finish
[color]
    ui = true
[core]
    excludesfile = /Users/nhyde/.gitignore_global
    ignorecase = false
    editor = vim
[push]
    default = matching

[[!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/debug.log


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

> Closing this because all autobuilders have been upgraded
> to a more recent version of git. done --[[Joey]] 
>> Reopened, because the Linux autobuilds have been downgraded to Debian
>> stable and have this problem again. --[[Joey]]

>>> Closing again! Autobuilders all run unstable and will have a current
>>> git. [[done]] --[[Joey]] 
