[PATCH] Fix handle leak in "git branch -D"

On Windows (it can't touch open files in any way) the following fails:

    git branch -D branch1 branch2

if the both branches are in packed-refs.

Signed-off-by: Alex Riesen <redacted>
---
 refs.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

BTW, why does not commit_lock_file takes care of closing the file
opened by hold_lock_file_for_update?