nix-prefetch-git: fix determinism with leaveDotGit#4767

bjornfor wants to merge 1 commit intoNixOS:masterNixOS/nixpkgs:masterfrom

bjornfor:fix-fetchgit-with-leavedotgitbjornfor/nixpkgs:fix-fetchgit-with-leavedotgitCopy head branch name to clipboard