Isolate IETF models in OpenConfig to own bundle

Change-Id: I15fff358582dd7b361d015c2d30c981a703fd1be
diff --git a/models/pom.xml b/models/pom.xml
index f8d7535..5b56d95 100644
--- a/models/pom.xml
+++ b/models/pom.xml
@@ -30,6 +30,7 @@
     <description>ONOS YANG models</description>
 
     <modules>
+        <module>ietf</module>
         <module>common</module>
         <module>microsemi</module>
         <module>openconfig</module>