Add is_shared attribute to network Model

is_shared reports whether a network is shared across all
vDCs within an organization, or just within the vDC it is defined in.

lib/fog/vcloud_director/models/compute/network.rb

@@ -13,6 +13,7 @@ module Fog
         attribute :href
         attribute :description
         attribute :is_inherited
+        attribute :is_shared
         attribute :fence_mode
         attribute :gateway
         attribute :netmask

lib/fog/vcloud_director/models/compute/networks.rb

@@ -20,6 +20,7 @@ module Fog
           service.add_id_from_href!(data)
           data[:name] = raw_network[:name]
           data[:description] = raw_network[:Description]
+          data[:is_shared] = raw_network[:IsShared]
           net_config = raw_network[:Configuration]
           data[:fence_mode] = net_config[:FenceMode]
           ip_scope = net_config[:IpScopes][:IpScope]

tests/vcloud_director/models/compute/network_tests.rb

@@ -58,6 +58,12 @@ Shindo.tests("Compute::VcloudDirector | networks", ['vclouddirector', 'all']) do
     end
   end
 
+  tests("Compute::VcloudDirector | network", ['is_shared is a string boolean']) do
+    tests("#is_shared is either 'true' or 'false'").returns(true) {
+      [ 'false', 'true' ].include?(network.is_shared)
+    }
+  end
+
   # NB: get_by_name is buggy with orgVdcNetworks - network names are only
   # unique per-vDC, not per organization.
   # As a result, it returns the *first* network matching that name.