[5.0 Vcenter] Ping to public isn't available from instnce without floating ip

[Olesia Tsvigun]

Fuel 9.0
fuel-plugin-contrail 5.0 buil#585

Steps to reproduce
    1. Connect to a Fuel with preinstalled Contrail plugin.
    2. Create a new environment with following parameters:
       * Compute: vCenter
       * Networking: Neutron with tunneling segmentation
       * Storage: default
       * Additional services: default
    3. Run script that prepares vmware part for deployment (creates few Distributed
       Switches and spawns virtual machine on each ESXi node)
    4. Configure Contrail plugin settings:
       * Datastore name
       * Datacenter name
       * Uplink for DVS external
       * Uplink for DVS private
       * DVS external
       * DVS internal
       * DVS private
    5. Add nodes with following roles:
       * Controller
       * ComputeVMWare
       * Contrail-vmware
       * Contrail-config + contrail-control + contrail-db + contrail-analytics
    6. Configure interfaces on nodes.
    7. Configure network settings.
    8. Configure VMware vCenter Settings:
       Add and assign 1 vCenter clusters to compute-vmware.
    9. Deploy the cluster.
    10. Launch instance with in the vcenter az, default internal net and sg.
    11. Check public conectivity from instance, try ping 8.8.8.8

Actual Result
Ping to 8.8.8.8 is not available.

Expected Result
Ping to 8.8.8.8 should be available.

[Vitalii Kovalchuk (vkovalchuk)]

https://review.openstack.org/#/c/378673/ -
in this patch we explicitly limit availability zone for SNAT netns.
The information about limitation for SNAT netns feature will be covered in documentation
https://review.openstack.org/#/c/313032/

[Olesia Tsvigun (otsvigun)]

Verified at contrail-5.0-5.0.0-1-674.noarch.rpm