git symbolic-ref --delete $symref

git symbolic-ref --delete $symref

Teach symbolic-ref to delete symrefs by adding the -d/--delete option to
git-symbolic-ref. Both proper and dangling symrefs are deleted by this
option, but other refs - or anything else that is not a symref - is not.

The symref deletion is performed by first verifying that we are given a
proper symref, and then invoking delete_ref() on it with the REF_NODEREF
flag.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>