Add a couple tweaks to the Dockerfile

- we don't need to add a "daemon" user to busybox; it already has one :)
- if we split out the "go get" from the "go install", we can have nice clean output on "docker build" of which dependencies we're pulling in and all the packages that get built :)

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Null-term ioctl ifr_name strings

Docker-DCO-1.1-Signed-off-by: Dhammika Pathirana <dhammika@gmail.com> (github: dhammika)
Fix veth network stats. Tx on the host vETH is ingress traffic and not egress.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Merge pull request #126 from dhammika/125-null-term-ifr_name

Null-term ioctl ifr_name strings #125
Merge pull request #121 from vishh/fix_network_stats

Fix veth network stats.
Merge pull request #123 from tianon/dockerfile-tweaks

Add a couple tweaks to the Dockerfile
netlink_linux: add remove address call, refactor add address call to
share code with remove address call.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)
netlink/netlink_linux_test.go: tests for netlink add/rem ip

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)