Add netaddr requirements for running ipv4|ipv6 filters

Running the ipv4 and ipv6 filters [1] requires the netaddr python
library to be installed on the Ansible *control node*, which ends up
being the executor.
These filters are very useful to determine if an IP is ipv4 or ipv6.

[1]: http://docs.ansible.com/ansible/latest/playbooks_filters_ipaddr.html

Change-Id: I800c7512fc60f9a302fb77cb061610430fcf8e49
1 file changed