Currently, the execution of site.yml fails as site.yml installs
python-netaddr in the same run as it uses it, which fails since
ansible-playbook can't see the newly installed module.
This commit simply removes python-netaddr from
mnaio_host_distro_packages and adds a new task to build.sh to
install it before site.yml is kicked off.
NOTE: This commit also switches to installing netaddr via pip
instead of system package since that does not require pre-loading
vars files depending on OS, etc.
Change-Id: I324ba61a860f5942b40972903ae1c40caa7839e5
e5ba32d8fa