[data processing] Fix UI refresh for deleted clusters

[Chad Roberts]

Priority *wishlist*

This is a fix that went into the sahara-dashboard repo after the merge process began. It needs to be merged into the new home in horizon.

Original patch: https://review.openstack.org/#/c/95042/

Steps to repro:
1. Create cluster
2. Goto clusters page
3. Click 'Delete Cluster'

Expected result: cluster is deleted and line with cluster removed from clusters list

Observed result: cluster is deleted, but line with cluster is still in the list. Page refresh helps.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/103963

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/103963
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=935a03080c477c3c34fea8a6ac8667543d8c7636
Submitter: Jenkins
Branch: master

commit 935a03080c477c3c34fea8a6ac8667543d8c7636
Author: Chad Roberts <email address hidden>
Date: Tue Jul 1 14:39:50 2014 -0400

    Data Processing: Fixing UI refresh for deleted clusters

    An Http404 is now returned when an update request comes
    in for a cluster that has been deleted which will trigger
    the appropriate UI update (removal of that cluster).

    Change-Id: I7216d361d3d09cb593b6ca2f3b89bfb9fc67917e
    Closes-Bug: bug #1336292
    Co-Authored-By: Andrew Lazarev <email address hidden>