[Sahara] AttributeError if open tab "job executions" and cluster for job execution is deleted

[Vadim Rovachev]

Steps to reproduce:
Create cluster with oozie
Create dependencies for job
Create and launch job
Wait end of job execution
Delete cluster for job execution
Open tab "job executions"

Expected result: tab opened

Actual result:
AttributeError at /project/data_processing/job_executions/
'NoneType' object has no attribute 'name'

sahara version: master
horizon version: master

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/136876

[OpenStack Infra (hudson-openstack)]

Change abandoned by Andrew Lazarev (<email address hidden>) on branch: master
Review: https://review.openstack.org/136876
Reason: Addressed by https://review.openstack.org/#/c/125927

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/125927
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=4f947f8cb21e68f3dffbeac52ad9b1e938946060
Submitter: Jenkins
Branch: master

commit 4f947f8cb21e68f3dffbeac52ad9b1e938946060
Author: Nikita Konovalov <email address hidden>
Date: Fri Oct 3 14:48:27 2014 +0400

    [Data_processing] fix job_executions table

    The table does not crash anymore after the cluster is deleted.
    Both the cluster object and the job are queried before extending a job execution.
    When the cluster or the job are deleted 'Not available' is assigned as the name.

    Closes-Bug: #1376738
    Closes-Bug: #1391356
    Closes-Bug: #1391507
    Change-Id: Iee60572f3a6e02447a6cd8508735bbb91ec020e9