[volume] Export syslog mgmt and facility through params

Refs: GH-78

spec/classes/cloud_volume_storage_spec.rb

@@ -32,7 +32,9 @@ describe 'cloud::volume::storage' do
         ks_keystone_internal_host  => '10.0.0.1',
         ks_cinder_password         => 'secrete',
         verbose                    => true,
-        debug                      => true }"
+        debug                      => true,
+        log_facility               => 'LOG_LOCAL0',
+        use_syslog                 => true }"
     end
 
     let :params do