Description of problem:
Registering a certain system causes 500 Internal Server error. This appears to be due to an interface on the client system that has no IP address.

Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/spacewalk/server/apacheRequest.py", line 129, in call_function
    response = func(*params)
  File "/usr/share/rhn/server/handlers/xmlrpc/registration.py", line 1030, in add_hw_profile
    if primif:
UnboundLocalError: local variable 'primif' referenced before assignment


Version-Release number of selected component (if applicable):
spacewalk-backend-xmlrpc-2.4.23-1.el6.noarch


How reproducible:
Always

This change fixes the problem for me:

--- /usr/share/rhn/server/handlers/xmlrpc/registration.py.orig	2016-02-17 14:02:46.742891028 -0800
+++ /usr/share/rhn/server/handlers/xmlrpc/registration.py	2016-02-17 13:40:28.343527458 -0800
@@ -1011,6 +1011,7 @@
         if row:
             ipaddr=row['ipaddr']
             ip6addr=row['ip6addr']
+            primif = None
             if ipaddr:
                 h = rhnSQL.prepare("""
                     select interface_id from rhnServerNetAddress4 where address = :address