[msysGit] make tests pass or disable them on MinGW

[Steffen Prohaska]

Hello Hannes,
I tweaked the tests for msysgit, such that they either pass or are  
disabled.  My commits are on branch work/tests (90fba70984) in  
4msysgit.  The branch is based on mingw/master.  So you can pull them  
if you like.

        Steffen