[UI] Cannot update nodegroups

[Evgeny Sikachev]

ENVIRONMENT: devstack master (10 march 2016)

STEPS TO REPRODUCE:
1. Create node group templates. For example(Ambari, 2.3):
      - name: master
        flavor: m1.small
        node_processes:
          - Ambari
          - MapReduce History Server
          - Spark History Server
          - NameNode
          - ResourceManager
          - SecondaryNameNode
          - YARN Timeline Server
          - Kafka Broker
        auto_security_group: true
2. Click on "Edit Template"
3. Add any process. For example: ZooKeeper
4. Click "Save"

EXPECTED RESULT:
NodeGroup updated

ACTUAL RESULT:
volumes_per_node: None is not of type 'integer'
Error ID: f391f226-5c68-42c2-afca-59d5dfa72255 (see Screenshot in attach)
And nodegroup not updated

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/292773

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/292773
Committed: https://git.openstack.org/cgit/openstack/sahara-dashboard/commit/?id=17f474ad659e2ebe48012b10b99e695755002a69
Submitter: Jenkins
Branch: master

commit 17f474ad659e2ebe48012b10b99e695755002a69
Author: Vitaly Gridnev <email address hidden>
Date: Tue Mar 15 12:15:41 2016 +0300

    Fix default value for volumes per node in updates

    None as a default value will cause problems with updates
    when volumes are unselected.

    Change-Id: I293300baea752aaf42c086f7b38327f43343e0f4
    Closes-bug: 1555496