Put back methods as instance methods

lib/vagrant/util/ipv4_interfaces.rb

@@ -1,13 +1,15 @@
 module Vagrant
   module Util
     module IPv4Interfaces
-      def self.ipv4_interfaces
+      def ipv4_interfaces
         Socket.getifaddrs.select do |ifaddr|
           ifaddr.addr && ifaddr.addr.ipv4?
         end.map do |ifaddr|
           [ifaddr.name, ifaddr.addr.ip_address]
         end
       end
+
+      extend IPv4Interfaces
     end
   end
 end

lib/vagrant/util/is_port_open.rb

@@ -13,7 +13,7 @@ module Vagrant
       # @param [Integer] port Port to check.
       # @return [Boolean] `true` if the port is open (listening), `false`
       #   otherwise.
-      def self.is_port_open?(host, port)
+      def is_port_open?(host, port)
         # We wrap this in a timeout because once in awhile the TCPSocket
         # _will_ hang, but this signals that the port is closed.
         Timeout.timeout(1) do
@@ -34,6 +34,8 @@ module Vagrant
         # Any of the above exceptions signal that the port is closed.
         return false
       end
+
+      extend IsPortOpen
     end
   end
 end