Adjust vbox hostonly config for ipv6

Check the type when an ipv6 address is being used. If the type does not
have a `6` suffix, append it.

plugins/providers/virtualbox/action/network.rb

@@ -302,6 +302,9 @@ module VagrantPlugins
             elsif ip.ipv6?
               options[:netmask] ||= 64
 
+              # Append a 6 to the end of the type if it is not already set
+              options[:type] = "#{options[:type]}6".to_sym if
+                !options[:type].to_s.end_with?("6")
             else
               raise IPAddr::AddressFamilyError, 'unknown address family'
             end

test/unit/plugins/providers/virtualbox/action/network_test.rb

@@ -62,6 +62,28 @@ describe VagrantPlugins::ProviderVirtualBox::Action::Network do
       expect(subject).to receive(:validate_hostonly_ip!)
       subject.hostonly_config(options)
     end
+
+    context "when address is ipv6" do
+      let(:address) { "::1" }
+
+      context "when type is static6" do
+        let(:type) { :static6 }
+
+        it "should have a static6 type" do
+          result = subject.hostonly_config(options)
+          expect(result[:type]).to eq(:static6)
+        end
+      end
+
+      context "when type is static" do
+        let(:type) { :static }
+
+        it "should have static6 type" do
+          result = subject.hostonly_config(options)
+          expect(result[:type]).to eq(:static6)
+        end
+      end
+    end
   end
 
   describe "#validate_hostonly_ip!" do