Overriding lbaas.py file

This patch is a forward-port of a patch from puppet-coe-service-patch
which had the following commit message:

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Revision: 4ee88b7361bc378b2f2dc6828d69838d914dd18a
Author: Ernest Millan <emillan@cisco.com>
Date: 7/9/2014 12:36:12 PM

    Overriding lbaas.py file and related puppet manifest update for TA2342
    Change-Id: Ifddb4036de15aad50a5ace0693fe297412cc389c

    "The current Horizon Load Balancer VIP input requires a user to input an IP
    address for the VIP on the subnet that the Load Balancer Pool is on.  From
    the CLI or API the neutron lb-vip-create takes a --subnet-id argument.  We
    need an enhancement so that user does not have to manually type in an IP
    from the subnet. Furthermore the neutron lp-pool has a param for subnet-id
    and the VIP gets associated to a pool as an optional param, or from Horizon
    you actually Add Vip under the LB Pool tab which inherently should already
    know what the subnet is. This is an unnecessary hardship for clients and
    prone to race conditions especially on shared networks."

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Implements: rally-user-story US4145
Implements: rally-task TA3483
Not-in-upstream: true