Since this parameter will be used on all daemon startups, it needs to be
available on all nodes. This is achieved by querying it via ssconf. This
patch additionally adds a getter method to readily retrieve the primary
ip family from a ConfigWriter object.

This patch also disables the 'R0904: Too many public methods' pylint
warning, as it crosses the 50 methods limit.

Signed-off-by: Manuel Franceschini <livewire@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>