Description of problem:
XMLRPC API call org.listOrgs() does not return key "system_groups".
According to API documentation this key is not optional.

Version-Release number of selected component (if applicable):
10.11
Also reproduced on Satellite 5.3 with API version 10.8

How reproducible:
Always

Steps to Reproduce:
1. See additional info.
2.
3.
  
Actual results:
The key "system_groups" is missing in the returned list of dictionaries.

Expected results:
According to API doc the key "system_groups" with integer value should be in the returned dictionary.

Additional info:
Simple Python reproducer script:
----------

#!/usr/bin/python

import xmlrpclib 

USER='admin'
PASS='pass'
SERVER='<SATELLITE_SERVER>'
client = xmlrpclib.Server("http://%s/rpc/api" % SERVER, verbose=0)
key = client.auth.login(USER, PASS)
result = client.org.listOrgs(key)
print(result)

----------

The output is:

[{'active_users': 2,
  'id': 1,
  'name': 'Testing org',
  'systems': 2,
  'trusts': 0},
 {'active_users': 1, 'id': 2, 'name': 'orga', 'systems': 0, 'trusts': 1},
 {'active_users': 1, 'id': 3, 'name': 'orgb', 'systems': 0, 'trusts': 1}]