I was wondering if it would be possible to change the git checkout code to execute the git check command with launchCommandWithCredentials(), instead of launchCommandIn().

With git-lfs 1.4.1, when a checkout occurs, it is smart enough to automatically fetch files. However, since GIT_SSH in unset, the lfs client fails to authenticate and the downloads fail. If we could get GIT_SSH set at checkout, then git-lfs would be able authenticate and the downloads would be successful.