Description

Steps to reproduce the issue:

1. run route/test_default_route.py get fail result in t0 topology
   2.Since EOS did not announce default route via BGP to DUT
   3.There is no related configuration in https://github.com/Azure/sonic-mgmt/blob/master/ansible/roles/eos/templates/t0-leaf.j2

Add following configuration manually on 4 EOS:
!
ip route 0.0.0.0/0 Null0
ipv6 route ::/0 Null0
router bgp 64600
redistribute static
!
which maked route/test_default_route.py passed.