+++ This bug was initially created as a clone of Bug #741476 +++

Description of problem:
API system.getDmi() method does not return any value if some row at DB is null 


Version-Release number of selected component (if applicable):
Spacewalk 1.6 Nightly Version


How reproducible:
100%


Steps to Reproduce:
 
  Reproducer available at BZ#741476

+++++++++++++++++++++++=


# python api-dmi.py

 { .. SNIP .. }

1000010003
{'product': '', 'vendor': '', 'bios_vendor': '', 'system': 'SYSTEM_MANUAL_FILLED', 'bios_release': '', 'board': '', 'bios_version': '1.17', 'asset': ''}
********************

  Changing DB: 

SQL> update rhnserverdmi set BIOS_VERSION = '' where SERVER_ID = 1000010003;

1 row updated.


SQL> select ID, BIOS_VENDOR, BIOS_VERSION, BIOS_RELEASE from rhnserverdmi where SERVER_ID = 1000010003;

	ID BIOS_VENDOR			  BIOS_VERSION	       BIOS_RELEASE
---------- ------------------------------ -------------------- ---------------
       184

SQL> select ID, SERVER_ID, VENDOR, SYSTEM, PRODUCT from rhnserverdmi whereSERVER_ID = 1000010003;  

	ID  SERVER_ID VENDOR			     SYSTEM				      PRODUCT
---------- ---------- ------------------------------ ---------------------------------------- --------------------------------------------------
       184 1000010003				     SYSTEM_MANUAL_FILLED

=================// ===================// =========

Executing python script: 


# python api-dmi.py

 { .. SNIP .. }

Traceback (most recent call last):
  File "api-dmi.py", line 12, in <module>
    sys_dmi = server.system.getDmi(token,int(system['id']))
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1224, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1570, in __request
    verbose=self.__verbose
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1264, in request
    return self.single_request(host, handler, request_body, verbose)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1297, in single_request
    return self.parse_response(response)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 1462, in parse_response
    p.feed(data)
  File "/usr/lib64/python2.7/xmlrpclib.py", line 557, in feed
    self._parser.Parse(data, 0)
xml.parsers.expat.ExpatError: XML or text declaration not at start of entity: line 1, column 76