schema-version added in VNFD, NSD, VLR, VNFR and NSR

Change-Id: I718533b5fd5dac26d07f2093f42485e56de6adc9
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/models/yang/nsd.yang b/models/yang/nsd.yang
index 6c8b8c5..55b40eb 100644
--- a/models/yang/nsd.yang
+++ b/models/yang/nsd.yang
@@ -308,6 +308,12 @@
 
   container nsd-catalog {
 
+    leaf schema-version {
+      description "Schema version for the NSD. If unspecified, it assumes v3.0";
+      type string;
+      default "v3.0";
+    }
+
     list nsd {
       key id;
 
diff --git a/models/yang/nsr.yang b/models/yang/nsr.yang
index 12cf850..4f2eb73 100644
--- a/models/yang/nsr.yang
+++ b/models/yang/nsr.yang
@@ -217,6 +217,12 @@
         key "id";
         unique "name";
 
+        leaf schema-version {
+          description "Schema version for the NSR. If unspecified, it assumes v3.0";
+          type string;
+          default "v3.0";
+        }
+
         leaf id {
           description "Identifier for the NSR.";
           type yang:uuid;
diff --git a/models/yang/vlr.yang b/models/yang/vlr.yang
index 6a9b591..9137539 100644
--- a/models/yang/vlr.yang
+++ b/models/yang/vlr.yang
@@ -50,6 +50,12 @@
 
   augment "/rw-project:project" {
     container vlr-catalog {
+      leaf schema-version {
+        description "Schema version for the VLR. If unspecified, it assumes v3.0";
+        type string;
+        default "v3.0";
+      }
+
       config false;
 
       list vlr {
diff --git a/models/yang/vnfd.yang b/models/yang/vnfd.yang
index d1c9df6..4816166 100644
--- a/models/yang/vnfd.yang
+++ b/models/yang/vnfd.yang
@@ -43,6 +43,12 @@
     description
       "Virtual Network Function Descriptor (VNFD).";
 
+    leaf schema-version {
+      description "Schema version for the VNFD. If unspecified, it assumes v3.0";
+      type string;
+      default "v3.0";
+    }
+
     list vnfd {
       key "id";
 
diff --git a/models/yang/vnfr.yang b/models/yang/vnfr.yang
index b669f97..6d23065 100644
--- a/models/yang/vnfr.yang
+++ b/models/yang/vnfr.yang
@@ -197,6 +197,12 @@
 
   augment "/rw-project:project" {
     container vnfr-catalog {
+      leaf schema-version {
+        description "Schema version for the VNFR. If unspecified, it assumes v3.0";
+        type string;
+        default "v3.0";
+      }
+
       config false;
       list vnfr {
         description