Always create router interface for ipv6 metadata test

Currently it was not created when firewall_driver='ovn' and
causing random issues with tests in some environments.
We need a router with subnet attached when using 'slaac'
as 'ra' and 'address' mode[1].

Also enable debug for bash script and encode
interface correctly[2].

[1] https://docs.openstack.org/neutron/latest/admin/config-ipv6.html#using-slaac-for-addressing
[2] Please URL encode % as %25, see RFC 6874

Related-Issue: #OSPCIX-565
Change-Id: Iaf44b791c575d0a0c93578ccab0c7f4dd40005b4
1 file changed