submodule update and core.askpass

[Dmitry Neverov <dmitry.neverov@jetbrains.com>]

Hi,

it seems like "git submodule update" command doesn't respect the
core.askpass option specified in a command line. I have a repository
with a submodule, I serve it over http which requires an authorization
and both main repository and submodule require the same credentials. I
run the following commands (pass.sh is a script which prints a password
to stdout):

git -c core.askpass=pass.sh clone main-repo
cd main-repo
git submodule init
git submodule sync
git -c core.askpass=pass.sh submodule update

The last command asks for a password interactively. 

I've run bisect, it seems like it started failing from commit
be8779f7ac9a3be9aa783df008d59082f4054f67. I've checked: submodule update
works fine in 1.8.5.rc2 with removed call to clear_local_git_env.

Is there any way to make git submodule update respect core.askpass
option, so one can use it in scripts?

-- 
Dmitry Neverov