test/case/infix_containers: ensure IP forwarding is enabled

Usually the CNI bridge plugin "takes care" of enabling IPv4 forwarding
on all interfaces, see issue #1125, but when the container tests are run
in a different order from the infix_containers.yaml, Infix may reset the
IPv4 forwarding on this critical interface.

This change is both future proof and also ensures the test works as it
was intended even if tests are run out-of-order.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

test/case/infix_containers/container_bridge/test.py

@@ -36,6 +36,7 @@ with infamy.Test() as test:
                         {
                             "name": f"{ifname}",
                             "ipv4": {
+                                "forwarding": True,
                                 "address": [{
                                     "ip": f"{DUTIP}",
                                     "prefix-length": 24