If you are using msysgit – they have just released a version that allows a config option to stop git hanging.
Fix is for https://github.com/msysgit/git/issues/101 in release https://github.com/msysgit/msysgit/releases/tag/Git-1.9.4-preview20140611
You can fix it by setting
git config --global sendpack.sideband false