commands/migrate: only checkout HEAD if repository isn't bare
commands/migrate: only checkout HEAD if repository isn't bare

dakotahawkins/git-lfs,github/git-lfs,aleb/git-lfs,aleb/git-lfs,github/git-lfs,github/git-lfs,dakotahawkins/git-lfs,dakotahawkins/git-lfs,aleb/git-lfs