Downloads can be flaky, so try downloading multiple times.
https://bugs.webkit.org/show_bug.cgi?id=105976

Patch by Tim 'mithro' Ansell <mithro@mithis.com> on 2013-01-03
Reviewed by Eric Seidel.

* Scripts/webkitpy/common/system/autoinstall.py:
(AutoInstaller._download_to_stream):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@138776 268f45cc-cd09-0410-ab3c-d52691b4dbfc