Different peer-id on different versions

Overview peer-id in full rib is different on oxygen and less, where router-id is taken instead of neighbor address/local-address from exabgp. On flurine there is neighbor address as it should be (imo).

Steps to reproduce

• install:feature odl-restconf odl-bgpcep-bgp odl-bgpcep-bgp-config-example
• conf_peer.py (configures internal neighbor ::1)
• env exabgp.tcp.port=1790 exabgp --debug default.cfg
  (starts exabgp with one ipv6 route)

In case of <=oxygen peer-id is set to 1.2.3.4 from router-id from exabgp config, even though there is no neighbor configured at that address.
Fluorine correctly assigns peer-id as ipv6 as is neighbor configuration and local-address in exabgp config.

fluorine output from full-rib

{
          "peer-id": "bgp://::1",
          "peer-role": "ibgp",
          "adj-rib-in": {
            "tables": [
              {

output from oxygen

{
          "peer-id": "bgp://1.2.3.4",
          "peer-role": "ibgp",
          "adj-rib-in": {
            "tables": [
              {

routes are the same in both cases, and are present in ipv6 topology as well.