kata_agent: ipv6: Ignore routes that have ipv6 gateway
kata_agent: ipv6: Ignore routes that have ipv6 gateway

We ignore routes that have an ipv6 destination, since kata agent
does not have support for ipv6 currently. We should do the same
for default route that has an ipv6 gateway address.

Fixes #672

Signed-off-by: Archana Shinde <047ac45ce396f63f3cf93ff43725668e736e0632@intel.com>

containers/virtcontainers,containers/virtcontainers