refs/files: fix issues with git-fetch on case-insensitive FS#5839

dscho wants to merge 4 commits into

git-for-windows:maingit-for-windows/git:mainfrom

gitgitgadget:kn/refs-files-case-insensitivegitgitgadget/git:kn/refs-files-case-insensitiveCopy head branch name to clipboard