Map allocation_pool property to set

If the user specifies an array of more than one allocation pool for the
neutron_subnet allocation_pool parameter, the order of the pools is not
guaranteed. On sequential puppet runs, puppet may error with "Property
allocation_pools does not support being updated" because the array is
read in a different order. To avoid this, define the insync? method to
compare the values as though they were unordered sets rather than
ordered lists.

Change-Id: I9c146b5abe563c7e6ebfed169e770ffe8e5cf94b

lib/puppet/type/neutron_subnet.rb

@@ -28,6 +28,9 @@ Puppet::Type.newtype(:neutron_subnet) do
     Array of Sub-ranges of cidr available for dynamic allocation to ports.
     Syntax:["start=IPADDR,end=IPADDR", ...]
     EOT
+    def insync?(is)
+      is.to_set == should.to_set
+    end
   end
 
   newproperty(:gateway_ip) do