Mark tegra2 bots as unimportant so they can be removed from the waterfall.
Mark tegra2 bots as unimportant so they can be removed from the waterfall.

BUG=chromium-os:33594
TEST=cbuildbot_config_unittest.py

Change-Id: Ied03dc9f8a678b8256cd40437f3df9b59f9dc375
Reviewed-on: https://gerrit.chromium.org/gerrit/30593
Commit-Ready: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Reviewed-by: Peter Mayo <3d31fdaf44dc55bb1b4f50b19df9bc879177d37a@chromium.org>

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