The ipfamilies parameter to the resolve_ipnets__netspec() helper
function was intended to be a list of IP address families (including
the special marker "__ANY").  However, in the case where no explicit
address family flag was passed to resolve_ipnets(), we passed in a
ipfamilies parameter of the string "__ANY", instead of a one-item
list of said string.  This happened to work under Ruby 1.8, where
strings have an #each method which works as if it was a one-item
list.  In Ruby 2.0, however, strings don't have a #each method.

Make sure to always pass in a list to resolve_ipnets__netspec().

This was originally commit dcc1f6df8e7f in nsc-puppet-utils.