Include secondary IP addresses in ip_addrs{,6}

These functions were not iterating over the list of secondary IP
addresses, causing grains['ipv4'] and grains['ipv6'], as well as the
module execution functions network.ip_addrs and network.ip_addrs6 to
fail to include these IPs. This commit fixes that oversight.
Merge pull request #6719 from terminalmage/issue6656

Include secondary IP addresses in ip_addrs{,6}