.refs test on Windows

[richardschneider]

The .refs test uses a symlink file that is in the git repository. On *nix ipfs add will use the contents of the target file. On Windows, the file is not a symlink, so ipfs add uses the contents of the file not the target.

This breaks the tests, because the hash of the top level directory is now different on Windows. See #644

[richardschneider]

It looks like #637 was closed prematurely.

[richardschneider]

From https://www.quora.com/How-does-git-handle-symbolic-links-on-Windows

In short: symlinks are not supported by git on Windows.
As a matter of fact, anyway, storing symlinks in git repositories is considered a bad practice.