new versions of `rspec-puppet-facts` can have no `ipaddress_eth0` fact

[igalic]

Depending on the version of facter and the OS it is run under, rspec-puppet-facts may come without an ipaddress_eth0 fact.

This can cause a great number of our tests to fail.

I'm not sure what the solution here is, since there's no clear progression to facter 3 style structured facts that give us the networking group:

{
  "dhcp": "192.168.1.1",
  "fqdn": "sinix",
  "hostname": "sinix",
  "interfaces": {
    "lo": {
      "bindings": [
        {
          "address": "127.0.0.1",
          "netmask": "255.0.0.0",
          "network": "127.0.0.0"
        }
      ],
      "bindings6": [
        {
          "address": "::1",
          "netmask": "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
          "network": "::1"
        }
      ],
      "ip": "127.0.0.1",
      "ip6": "::1",
      "mtu": 65536,
      "netmask": "255.0.0.0",
      "netmask6": "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
      "network": "127.0.0.0",
      "network6": "::1"
    },
    "wlp4s0": {
      "bindings": [
        {
          "address": "192.168.1.131",
          "netmask": "255.255.255.0",
          "network": "192.168.1.0"
        }
      ],
      "bindings6": [
        {
          "address": "fe80::d1ca:8b89:40d5:f5be",
          "netmask": "ffff:ffff:ffff:ffff::",
          "network": "fe80::"
        }
      ],
      "dhcp": "192.168.1.1",
      "ip": "192.168.1.131",
      "ip6": "fe80::d1ca:8b89:40d5:f5be",
      "mac": "f8:16:54:67:5c:37",
      "mtu": 1500,
      "netmask": "255.255.255.0",
      "netmask6": "ffff:ffff:ffff:ffff::",
      "network": "192.168.1.0",
      "network6": "fe80::"
    }
  },
  "ip": "192.168.1.131",
  "ip6": "fe80::d1ca:8b89:40d5:f5be",
  "mac": "f8:16:54:67:5c:37",
  "mtu": 1500,
  "netmask": "255.255.255.0",
  "netmask6": "ffff:ffff:ffff:ffff::",
  "network": "192.168.1.0",
  "network6": "fe80::",
  "primary": "wlp4s0"
}

facter2 facts, even when structured, don't come with that group at all, making it more difficult to find the primary interface.