CI: set -o pipefail #nitpick

This way if the `curl` theoretically fails, then even though subsequent
commands in the pipeline will probably exit with non-zero status,
CircleCI will mark this script as a failure.

We don't do this anywhere else because this is the only pipeline at the
end of a CircleCI script.
diff --git a/circle.yml b/circle.yml
index 35eaeff..75229ab 100644
--- a/circle.yml
+++ b/circle.yml
@@ -119,6 +119,7 @@
       fi
       build_name="$build_name @ ${CIRCLE_SHA1:0:7}"
 
+      set -o pipefail
       curl -i -X POST https://saucelabs.com/rest/v1/$SAUCE_USERNAME/js-tests \
            -u $SAUCE_USERNAME:$SAUCE_ACCESS_KEY \
            -H 'Content-Type: application/json' \