Description of problem:
In IPv6 deployments my_ip parameter in nova.conf on the compute nodes gets set on the tenant tunelling network.

Version-Release number of selected component (if applicable):
openstack-tripleo-heat-templates-0.8.14-5.el7ost.noarch

How reproducible:
100%

Steps to Reproduce:
1. Deploy IPv6 enabled overcloud
2. Check my_ip paramater in nova.conf on one of the computes

Actual results:
[root@overcloud-novacompute-0 heat-admin]# grep my_ip /etc/nova/nova.conf | grep -v ^#
my_ip=172.16.22.11

stack@instack:~>>> neutron subnet-list | grep tenant
| bef32c7b-66a9-4cf7-aee2-a4abae05d6e5 | tenant_subnet       | 172.16.22.0/24           | {"start": "172.16.22.10", "end": "172.16.22.100"}                                      |

Expected results:
I would expect the my_ip paramater to be set from the internal_api subnet.

Additional info:

The host_ip property of the compute node shows the IP from the tenant tunelling subnet:

stack@instack:~>>> nova hypervisor-show overcloud-novacompute-0.localdomain
+---------------------------+------------------------------------------+
| Property                  | Value                                    |
+---------------------------+------------------------------------------+
| cpu_info_arch             | x86_64                                   |
| cpu_info_features         | ["pge", "clflush", "sep", "syscall",     |
|                           | "msr", "cmov", "fpu", "pat", "lm",       |
|                           | "tsc", "nx", "fxsr", "pae", "mmx",       |
|                           | "cx8", "mce", "de", "mca", "pse", "pni", |
|                           | "apic", "sse", "lahf_lm", "sse2",        |
|                           | "hypervisor", "cx16", "pse36", "mtrr",   |
|                           | "x2apic"]                                |
| cpu_info_model            | cpu64-rhel6                              |
| cpu_info_topology_cells   | 1                                        |
| cpu_info_topology_cores   | 1                                        |
| cpu_info_topology_sockets | 2                                        |
| cpu_info_topology_threads | 1                                        |
| cpu_info_vendor           | Intel                                    |
| current_workload          | 0                                        |
| disk_available_least      | 38                                       |
| free_disk_gb              | 40                                       |
| free_ram_mb               | 7791                                     |
| host_ip                   | 172.16.22.11                             |
| hypervisor_hostname       | overcloud-novacompute-0.localdomain      |
| hypervisor_type           | QEMU                                     |
| hypervisor_version        | 2003000                                  |
| id                        | 2                                        |
| local_gb                  | 40                                       |
| local_gb_used             | 0                                        |
| memory_mb                 | 9839                                     |
| memory_mb_used            | 2048                                     |
| running_vms               | 0                                        |
| service_disabled_reason   | None                                     |
| service_host              | overcloud-novacompute-0.localdomain      |
| service_id                | 26                                       |
| state                     | up                                       |
| status                    | enabled                                  |
| vcpus                     | 2                                        |
| vcpus_used                | 0                                        |
+---------------------------+------------------------------------------+