Updated msysgit to 1.8.5.2

Don't stick with 1.8.4 because a regression in this version brake git-svn and git-tfs...

http://thread.gmane.org/gmane.comp.version-control.git/234434
https://groups.google.com/forum/#!topic/msysgit/9K-hozPjMDs
https://github.com/git-tfs/git-tfs/issues/448