In test_dscp_marking_packets, sender vm is sending ICMP packets to the
Before this patch even if first ICMP packet wasn't send properly, test
failed due to exception raised in execute method.
It can happend sometimes that first packet will fail to be send as there
can be e.g. some configuration on agent's side not done yet. So we
should try to ping receiver_vm for 60 seconds instead of failing on
This patch changes that behaviour in test.