Better default for my_ip if 8.8.8.8 is unreachable
Better default for my_ip if 8.8.8.8 is unreachable

Run if route/show, extract ipv4 addresses and pick the first one.
Fall back to 127.0.0.1 as before if we don't find anything
or if we have running the ip route/show commands

Fixes LP# 1193013

Change-Id: If73f0f6bf67f858f7506220debab0f74cc9e3cb4

openstack/oslo.versionedobjects,citrix-openstack-build/oslo.versionedobjects