workarounds #80
workarounds #80

- when /Library/Preferences/SystemConfiguration/com.apple.vmnet.plist is not yet
  available in the local filesystem (because Internet Sharing wasn't used or
  activated yet, or whatever) we'd just assume that the macOS defaults will be
  used instead of failling inconditionally

Signed-off-by: António Meireles <9056f7c1f560fe4e0c75ab3cde8bee0cf3d504f4@reformi.st>

TheNewNormal/corectl,AntonioMeireles/coreos-xhyve,TheNewNormal/corectl,AntonioMeireles/coreos-xhyve