Minor fixes at sdn-port-mapping

Change-Id: I00e8bed1ab97d75654e2eb7ddc330689abde7fcf
Signed-off-by: tierno <alfonso.tiernosepulveda@telefonica.com>
diff --git a/osm_ro/nfvo.py b/osm_ro/nfvo.py
index 7a3e959..282b7f3 100644
--- a/osm_ro/nfvo.py
+++ b/osm_ro/nfvo.py
@@ -4357,6 +4357,7 @@
 
 
 def new_datacenter(mydb, datacenter_descriptor):
+    sdn_port_mapping = None
     if "config" in datacenter_descriptor:
         sdn_port_mapping = datacenter_descriptor["config"].pop("sdn-port-mapping", None)
         datacenter_descriptor["config"] = yaml.safe_dump(datacenter_descriptor["config"], default_flow_style=True,