[LBaaS] Add VIP requires knowing a free ip address instead of subnet

[Yves-Gwenael Bourhis]

When following this procedure:
https://wiki.openstack.org/wiki/Neutron/LBaaS/HowToRun
Neutron CLI allows specifying a subnet:

    neutron lb-vip-create --name myvip --protocol-port 80 --protocol HTTP --subnet-id <subnet-id> mypool

And a free IP from the subnet will be assigned to the VIP.

The horizon Form requires knowing in advance an unused IP from the subnet.
Also, if we do not fill this part of the form with an IP (not marked as compulsory in the form), we get the following error:
'Error: Unable to add VIP "myvip".'

Also, the is detected, because the form mentions "Specify a free IP address from <subnet mentioned here>".

[Leandro Ignacio Costantino (leandro-i-costantino)]

Address is set to empty, so 'invalid address' is returned.

{"vip": {"session_persistence": {}, "protocol": "HTTP", "name": "MyVip", "address": "", "subnet_id": "6b69d9cd-f2fc-4cea-b237-a645ec34af5c", "protocol_port": 55, "admin_state_up": true, "pool_id": "99a1713d-58cc-433b-9932-f3a8c4f524ea", "description": "A vip w/o free ip "}}

HTTP/1.1 400 Bad Request
Content-Length: 84
Content-Type: application/json; charset=UTF-8

{"NeutronError": "Invalid input for address. Reason: '' is not a valid IP address."}

The field can be removed or set to null ( None before json conversion ) if not mandatory

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/57451

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/57451
Committed: http://github.com/openstack/horizon/commit/b5392a80a3d1157ee6e16adc467939ee79b1911c
Submitter: Jenkins
Branch: master

commit b5392a80a3d1157ee6e16adc467939ee79b1911c
Author: Leandro I. Costantino <email address hidden>
Date: Wed Nov 20 09:56:58 2013 -0500

    VIP creation fails if ip address is not specified.

    Neutron Client allows creation of VIP by specifying only
    a subnet. In that case a free ip from that subnet will be
    asigned.
    When creating the VIP from Horizon, if the ip address is not
    set on them form, the request for VIP creation will include
    an empty address and fail.
    If the address is not set or empty, don't send that key
    since it's not mandatory.

    Change-Id: Id9b8f4aa187eae65f5b87c742309e0e39c804208
    Closes-Bug: #1252811