Description of problem:
If you create new note for a specific software crash without Details filled in and then fetch all crash notes for the crash using API, it fails with traceback.

Version-Release number of selected component (if applicable):
Satellite-5.6.0-RHEL6-re20130502.1
spacewalk-abrt-1.9.6-1.el6sat.noarch

How reproducible:
always

Steps to Reproduce:
1. create software crash for the system
2. create crash note without Details for the system
3. run system.crash.getCrashNotesForCrash(key, crid) API call
4. check the traceback
  
Actual results:
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python2.6/xmlrpclib.py", line 1199, in __call__
    return self.__send(self.__name, args)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 1489, in __request
    verbose=self.__verbose
  File "/usr/lib64/python2.6/xmlrpclib.py", line 1253, in request
    return self._parse_response(h.getfile(), sock)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 1387, in _parse_response
    p.feed(response)
  File "/usr/lib64/python2.6/xmlrpclib.py", line 601, in feed
    self._parser.Parse(data, 0)
xml.parsers.expat.ExpatError: XML or text declaration not at start of entity: line 1, column 649

Expected results:
[{'updated': '5/3/13 9:23:34 AM EDT', 'subject': 'test', 'details': '', 'id': 7}]

Or in WebUI Details should be required as well as Subject.