bugfix(ip/mac): increments only in extra VDU, not the first one. Bug 1578

Change-Id: I21a0c2e15934e58d22a3a373a6ea6ef68c9b6ebf
Signed-off-by: bravof <fbravo@whitestack.com>
diff --git a/osm_nbi/instance_topics.py b/osm_nbi/instance_topics.py
index dc85a50..4e88de5 100644
--- a/osm_nbi/instance_topics.py
+++ b/osm_nbi/instance_topics.py
@@ -937,9 +937,9 @@
             for index in range(0, count):
                 vdur = deepcopy(vdur)
                 for iface in vdur["interfaces"]:
-                    if iface.get("ip-address"):
+                    if iface.get("ip-address") and index != 0:
                         iface["ip-address"] = increment_ip_mac(iface["ip-address"])
-                    if iface.get("mac-address"):
+                    if iface.get("mac-address") and index != 0:
                         iface["mac-address"] = increment_ip_mac(iface["mac-address"])
 
                 vdur["_id"] = str(uuid4())