zebra: fix removed default route at vrf enabling

When a routing table (RT) already has a default route before being
assigned to a VRF, the default route vanishes in zebra after the VRF
assignment.

> root@router:~# ip route add blackhole default table 100
> root@router:~# ip route show table 100
> blackhole default
> root@router:~# vtysh -c 'show ip route table 100'
> [...]
> VRF default table 100:
> K>* 0.0.0.0/0 [0/0] unreachable (blackhole), 00:00:05
> root@router:~# ip l add red type vrf table 100
> root@router:~# vtysh -c 'show ip route table 100'
> root@router:~#

Do not override the default route if it exists.

Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>

0 files changed, 0 insertions, 0 deletions