Supports IPv6 in registry_host

This patch add support for IPv6 address in registry_host.
It adds brackets if an IPv6 is detected.

Change-Id: Ic1d75984fac7bce3d0239df54a877ae2b713c442

spec/classes/glance_api_spec.rb

@@ -307,6 +307,17 @@ describe 'glance::api' do
     )}
   end
 
+  describe 'Support IPv6' do
+    let :params do
+      default_params.merge({
+        :registry_host => '2001::1',
+      })
+    end
+    it { is_expected.to contain_glance_api_config('DEFAULT/registry_host').with(
+      :value => '[2001::1]'
+    )}
+  end
+
   describe 'on Debian platforms' do
     let :facts do
       @default_facts.merge({