Since git-client 1.5.0, reference repositories are not correctly resolved anymore.

Commit a3d3d548 (replace "clone" by "init+fetch" so we can configure git to use a local gitcrendentials store) introduced two problems:

• alternates is made to point to <referencePath>/.git/objects which obviously can not work for bare reference repositories (which should be the rule).
• alternates uses File.getAbsolutePath() which uses backslashes on windows systems. However, both msysgit and cygwin-git expect slashes as path divider