toolchain_build: Use new URL for git repositories
toolchain_build: Use new URL for git repositories

The chromium.googlesource.com URL is backed by more resources than
git.chromium.org.  As right now most of the time our bots spend is
in the 'git fetch' stages, we can at least hope that the large-scale
servers might speed up our cycle times.

BUG= none
TEST= locally verified new URL works

R=bradnelson@google.com

Review URL: https://codereview.chromium.org/11448022

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@10388 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

nacl-webkit/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client