add init method for ns_config

Signed-off-by: Mike Marchetti <mmarchetti@sandvine.com>
diff --git a/osmclient/v1/ns.py b/osmclient/v1/ns.py
index 8ea1854..65f816d 100644
--- a/osmclient/v1/ns.py
+++ b/osmclient/v1/ns.py
@@ -113,6 +113,8 @@
 
             nsr['ssh-authorized-key'] = ssh_keys_format
 
+        ns_config = {}
+
         if config: 
             ns_config = yaml.load(config)