bug: depth 1 and recursive update of submodules broke in 2.9.0

When I try to ```git clone --depth 1 --recursive https://github.com/davidhalter/jedi-vim.git``` in 2.9.0, it fails with the message: ``` Cloning into 'jedi-vim'... remote: Counting objects: 37, done. remote: Compressing objects: 100% (27/27), done. remote: Total 37 (delta 1), reused 16 (delta 0), pack-reused 0 Unpacking objects: 100% (37/37), done. Checking connectivity... done. Submodule 'jedi' (https://github.com/davidhalter/jedi.git) registered for path 'jedi' Cloning into '/home/stephanos/jedi-vim/jedi'... error: no such remote ref 995a6531225ba0b65e1ff863d97e5404d989047b Fetched in submodule path 'jedi', but it did not contain 995a6531225ba0b65e1ff863d97e5404d989047b. Direct fetching of that commit failed. ```, while with git 2.8.3 it succeeds. The commit 995a6531225ba0b65e1ff863d97e5404d989047b exists.

See the discussion and bug fix at http://thread.gmane.org/gmane.comp.version-control.git/297687/focus=297719

This is a known regression in 2.9.0 and the fix is in the master branch already. (I think Junio will also roll it into 2.9.1)