Enable uploading of hwtest artifacts on all chromium PFQs.
Enable uploading of hwtest artifacts on all chromium PFQs.

If we upload hwtest artifacts, it makes it easier for developers
to reproduce any problems with the tests because the autotest
tarball will be in Google Storage.

rkc@ mentioned that he uses this tarball to debug failures in the
Chromium PFQ.

BUG=chromium-os:34723
TEST=cbuildbot_config_unittest.py

Change-Id: I00ecb9cb5eaca5d29a64e70e745989a0f916e388
Reviewed-on: https://gerrit.chromium.org/gerrit/33925
Reviewed-by: Rahul Chaturvedi <4daac3e8e16f1590440c06bbd944ab7fcb8de43e@chromium.org>
Reviewed-by: Peter Mayo <3d31fdaf44dc55bb1b4f50b19df9bc879177d37a@chromium.org>
Commit-Ready: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>

zhang0137/chromite,coreos/chromite,bpsinc-native/src_third_party_chromite,coreos/chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,zhang0137/chromite,zhang0137/chromite,chadversary/chromiumos.chromite,coreos/chromite,bpsinc-native/src_third_party_chromite