[Docker] Docker apps failed to deploy due AttributeError: 'list' object has no attribute 'copy'

[Victor Ryzhenkin]

Steps:
1. Add docker apps from a.o.o(or use it from master branch, it doesn't matter)
2. Deploy any docker app

The error appears:
AttributeError: 'list' object has no attribute 'copy'

engine logs attached

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/294603

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/294603
Committed: https://git.openstack.org/cgit/openstack/murano/commit/?id=5fcbdccbedd4c3ae9f13a30a82514cefc789c3bf
Submitter: Jenkins
Branch: master

commit 5fcbdccbedd4c3ae9f13a30a82514cefc789c3bf
Author: Stan Lagun <email address hidden>
Date: Fri Mar 18 16:54:47 2016 +0300

    Removes ability to alter defaults for child objects

    Previously there was a feature which allowed to set
    new default property values for owned objects
    when using class() contract. This was done using
    Default property keyword which served for 2 different
    purposes in this case. The feature was never used neither
    documented anywhere. And it wasn't ever really designed.
    It also had a bug that caused default value [] (empty list)
    to be replaced with {} (empty dict).

    But there are cases when instead of $.class() contract
    we have [$class()] contract and in this case default
    value should also be a list rather then a dictionary of
    property values. So the only reason some applications
    worked until recently was that bug.

    However recent refactoring reworked that code and
    fixed that bug. So, in turn, it broke all docker applications
    that implicitly relied on that bug.

    This commit removed the entire feature. It was never
    used thus will break. We can reconsider it once we have
    a better design and use cases for it.

    Change-Id: I792fbd9801ff7776ee72660b2be2f89d0bfeb132
    Closes-Bug: #1558332