Incorrect rendering of distribution pie chart when all values are zero

[Ana Krivokapić]

It can be reproduced using this distribution:

<div class="d3_pie_chart_distribution"
  data-used="Controller=0|Compute=0|Object Storage=0|Block Storage=0">
</div>

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/78743

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/78743
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=1b7e1a65256814e5a741748b1d571fc99b3508ca
Submitter: Jenkins
Branch: master

commit 1b7e1a65256814e5a741748b1d571fc99b3508ca
Author: Ana Krivokapic <email address hidden>
Date: Thu Mar 6 21:05:41 2014 +0100

    Fix distribution pie chart

    When all values are zero, distribution pie chart should render as
    an empty chart.

    Change-Id: I5b08f6ed3d65029b75c4bb23c162fc45ac4e45ff
    Closes-Bug: #1288698