golang api fails to update network-ipam refs

[Pedro Marques]

The generated golang API classes have a problem when dealing with updates.

The contrail-api supports updating a reference field as a write with the full content (via the PUT method of the object) or as a ADD/DELETE operation via the update-refs URI.

The desired outcome is to use the PUT method when:
  1. The new set of refs is empty.
  2. The old set of refs is empty.
  3. The old set of refs is unknown (since the Clear operation doesn't perform a read of the refs).

Otherwise, when the previous list of refs is known, the code should use the "update-refs" URI.

The current code incorrectly assumes that the current set of refs is the empty set when a Clear operation is issued and the
refs field is no marked as valid.

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/16849
Submitter: Pedro Marques (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/16849
Committed: http://github.org/Juniper/contrail-generateDS/commit/217bbb0ef47ae81e85e1de75bf8b3d7e3338f7c7
Submitter: Zuul
Branch: master

commit 217bbb0ef47ae81e85e1de75bf8b3d7e3338f7c7
Author: Pedro Roque Marques <email address hidden>
Date: Wed Feb 3 16:36:57 2016 -0800

Fix the logic regarding reference updates.

References can be updated via the PUT operation on the object
or via the update-ref URI. Ensure that they are only done via
one of these mechanisms (not both on the same update).

Reference clear operations do not perform a read. Do not store
the current value of the reference list when it is unknown.

Fix the copying of the data used to compare references.

Change-Id: Ie24588d315f0c70f48040258c1b270b0b84a85d5
Closes-bug: #1541654