Reset Get-LocalOrParentPath() checkin name

commit 72fde6f made $pathToTest use Join-Path and in the process dropped the
fullname from $checkin. On my system, this had the negative of introducing as
PS to my prompt when outside of a git repository. Restoring $checkIn.fullname
leaves the path on the prompt an expected c:\path> instead of c:\pathPS>
maybe fix?