Need provision to specify multiple private subnets behind onPrem

[Senthilnathan Murugappan]

We have multiple private networks (eg: 192.168.1.0.24 and 192.168.2.0/24) behind the OnPrem GW.
Currently we can specify only one private_subnet under instances of Gateway role.
We need a way to specify multiple private subnets.

2c9ce5b6c835:~/multicloud# transform/generate_inventories.py -t topology.yml -s secret.yml -ts terraform.tfstate
Traceback (most recent call last):
  File "transform/generate_inventories.py", line 449, in <module>
    contrail_config=contrail_config)
  File "transform/generate_inventories.py", line 402, in initialize
    return invObj.output_inventory(gateways, contrail, tor, onprem_ospf, state, contrail_config)
  File "transform/generate_inventories.py", line 350, in output_inventory
    contrail_config = self.prepare_contrail_config(self.instances, contrail_common)
  File "transform/generate_inventories.py", line 256, in prepare_contrail_config
    network = IPNetwork(instance.private_subnet)
  File "/usr/lib/python2.7/site-packages/ipaddr.py", line 124, in IPNetwork
    address)
ValueError: '192.168.2.0/24, 192.168.1.0/24' does not appear to be an IPv4 or IPv6 network

[Paweł Kopka (pkopka)]

I added support for multiply subnet for onprem provider.
https://github.com/Juniper/contrail-multi-cloud/pull/176/

To use it You need put list in private_subnet, for example:

      private_subnet:
        - 172.168.1.0/24
        - 172.168.2.0/24

Order have matter, always first subnet will be treat as primary. In example 172.168.1.0/24.