Merge branch 'alexxxxx-feature/fixing-typo' into develop

Merged from: https://github.com/Icinga/puppet-icinga2/pull/81/

templates/object_notification.conf.erb

@@ -54,7 +54,7 @@ object Notification "<%= @object_notificationname %>" {
   <%- end -%>
   <%- if @interval -%>
 
-  interval = <%= @inteval %>
+  interval = <%= @interval %>
   <%- end -%>
   <%- if @period -%>