Flush LanItems#Items cache when importing AY profile. bnc#866742

LanItems#Items should correspond exactly to the content of
NetworkInterfaces cache. So, it has to be dropped and reinitialized
according the new NetworkInterfaces' content.

It (only) partly addresses bnc#866742.

src/modules/LanItems.rb

@@ -1096,6 +1096,8 @@ def Read
     # @param [Hash] AY profile converted into hash
     # @return [Boolean] on success
     def Import(settings)
+      LanItems.Items = {}
+
       NetworkInterfaces.Import("netcard", settings["devices"] || {})
       NetworkInterfaces.List("netcard").each do |device|
         AddNew()