dahlbyk/posh-git — pull request #86 by Haacked (2013-03-22 03:03:24+00:00)
Title: Stop error message when id_rsa is missing

Since we set the $Env:HOME when we launch our Git Shell, we hit
this new code path which joins that path with the .ssh\id_rsa file.
Problem is, that file doesn't exist so we get ssh-add taking a long
time and reporting an error.

This code path should do the same thing as the old one and return
null if the file doesn't exist.