Validate that swift zones are integers.

As per the docs, zones are numbers starting at 1.
http://docs.openstack.org/developer/swift/deployment_guide.html#preparing-the-ring

Change-Id: I9bcc1616ad266b09ae4be65bf35b31ea0a455af7

manifests/storage/node.pp

@@ -15,6 +15,8 @@ define swift::storage::node(
   $manage_ring = true
 ) {
 
+  validate_re($zone, '^\d+$', 'The zone parameter must be an integer')
+
   Swift::Storage::Server {
     storage_local_net_ip => $storage_local_net_ip,
     devices              => $mnt_base_dir,

spec/defines/swift_storage_node_spec.rb

@@ -31,4 +31,18 @@ describe 'swift::storage::node' do
     should contain_ring_container_device("127.0.0.1:6011/1")
     should contain_ring_account_device("127.0.0.1:6012/1")
   }
+
+  context 'when zone is not a number' do
+     let(:title) { '1' }
+     let :params do
+     { :zone => 'invalid',
+       :mnt_base_dir => '/srv/node' }
+     end
+
+    it 'should raise an error' do
+      expect {
+        subject
+      }.to raise_error(Puppet::Error, /The zone parameter must be an integer/)
+    end
+  end
 end