70999e9cec (branch -m: update all per-worktree HEADs - 2016-03-27)
added this function in order to update HEADs of all relevant
worktrees, when a branch is renamed.
It, as a public ref api, kind of breaks abstraction when it uses
internal functions of files backend. With the introduction of
refs_create_symref(), we can move back pretty close to the code before
70999e9cec, where create_symref() was used for updating HEAD.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
d026a25657