heat object field nullable is False by default

[Kanagaraj Manickam]

in Heat objects, the default value of nullable attribute is set in many of the object's fields, which is not required as oslo object Field defines nullable as False by default

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/170775

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/170775
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=39368e2f6ad7b0b77fdd0581105d399fc84c296f
Submitter: Jenkins
Branch: master

commit 39368e2f6ad7b0b77fdd0581105d399fc84c296f
Author: Kanagaraj Manickam <email address hidden>
Date: Fri Apr 3 12:27:38 2015 +0530

    Cleans default declaration nullable=False from heat objects

    In Heat objects, the default value of nullable attribute is
    set in many of the object's fields, which is not required
    as oslo object Field defines nullable as False by default

    Change-Id: I0164b64c043816f624aeba19561a4a5f8d36689d
    Closes-bug: #1439957