seems wrong with network.Bridge initializer

[Cheng Yu]

I just record issue I found, after I got through all of this book, I will submit pr for it.

seems the struct initializer in code-6.5 are wrong.
in branch code-6.5 network/bridge.go
br := &netlink.Bridge{la}
addr := &netlink.Addr{ipNet}
will cause "too few values in struct initializer"

[Bingshen Wang]

Cause of go netlink library modify the struct field. PR is welcome.