Difference in docker 1.10.3 when running container with -net=none

General Discussions
1

When I run the following command on docker 1.10.3 and 1.9.1:
docker run -itd --net=none --name=test_container busybox

I got different /etc/hosts content inside the container:
docker 1.10.3:
127.0.0.1 localhost
…
ff02::2 ip6-allrouters
c84a3bb41f8f

docker 1.9.1:
127.0.0.1 localhost
…
ff02::2 ip6-allrouters

In docker 1.10.3 container, the /etc/hosts file has an extra line of the container id but isn’t mapped to any address.
This breaks my existing software which ran well on 1.9.1 before.

I’m wondering whether the new line was introduced on purpose? Is there any way to avoid the extra line?