Fix bug 1159: vdu can be empty in a KNF, override option must take it into account

Change-Id: I1947d65ab55af825f7aaa90b4fbf2f6e8f5a7a4b
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/osmclient/sol005/vnfd.py b/osmclient/sol005/vnfd.py
index 48fbdb7..ac44495 100644
--- a/osmclient/sol005/vnfd.py
+++ b/osmclient/sol005/vnfd.py
@@ -204,7 +204,8 @@
                 for k in vnfd:
                     # Get only the first descriptor in case there are many in the yaml file
                     # k can be vnfd:vnfd-catalog or vnfd-catalog. This check is skipped
-                    vdu_list = vnfd[k]['vnfd'][0]['vdu']
+                    first_vnfd = vnfd[k]['vnfd'][0]
+                    vdu_list = first_vnfd.get('vdu',[])
                     break;
                 for vdu_number, vdu in enumerate(vdu_list):
                     if override_epa: