Try setting the post-buffer to avoid ssh errors with kiln.

Summary:
We've been having trouble with kiln timing out on us for pulls and
pushes to the translations repo.  Talking to kiln customer support, they
said this:

    This might seem a bit random - however there seems to be
    anaecdotal evidence that setting the post buffer may help (even
    with SSH).

    Maybe something like

    git config --global http.postBuffer 629145600

So let's try it.

Test Plan: Fingers crossed.

Reviewers: chris

Reviewed By: chris

Differential Revision: http://phabricator.khanacademy.org/D7890
Merge branch 'master' of github.com:Khan/aws-config