git-branch: show detached HEAD
git-branch: show detached HEAD

This makes git-branch show a detached HEAD as '* (no branch)'.

Signed-off-by: Lars Hjemli <1022a68b169538dabe33b1e3a08dffa0cefd6c22@gmail.com>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git