need to fix CommonDisambiguationError

[redilonka]

str: (ct/teach/courses/4/units/16/concepts/231/errors/)

1. open courses
2. open units
3. open concepts
4. open errors
5. search=tr
6. Link to this Concept

AR: Exception: There are more than one articles for that query
ER: Link to this Concept

Traceback:
File "/home/wwwapps/_ve_socraticqs2/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/wwwapps/_ve_socraticqs2/local/lib/python2.7/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
  22.                 return view_func(request, *args, **kwargs)
File "/home/wwwapps/socraticqs2/mysite/ct/views.py" in concept_errors
  732.                   unit=unit, showConceptAction=True, isError=True)
File "/home/wwwapps/socraticqs2/mysite/ct/views.py" in _concepts
  539.                                         request.user)
File "/home/wwwapps/socraticqs2/mysite/ct/models.py" in get_from_sourceDB
  27.         lesson = Lesson.get_from_sourceDB(sourceID, user, sourceDB)
File "/home/wwwapps/socraticqs2/mysite/ct/models.py" in get_from_sourceDB
  262.         data = dataClass(sourceID)
File "/home/wwwapps/socraticqs2/mysite/ct/sourcedb_plugin/wikipedia_plugin.py" in __init__
  17.             raise CommonDisambiguationError(getattr(e, 'options'))

Exception Type: CommonDisambiguationError at /ct/teach/courses/4/units/16/concepts/231/errors/
Exception Value: There are more than one articles for that query

[alexbojko]

In file ct/views.py:553

elif 'search' in request.GET:
        searchForm = ConceptSearchForm(request.GET)
        if searchForm.is_valid():
            s = searchForm.cleaned_data['search']
            if errorModels is not None: # search errors only
                cset = [
                    (
                        ul.lesson.title,
                        get_object_url(request.path, ul),
------>                 ul # here was no ul, so cset was a list of tuples with 2 elements
                    )
                    for ul in UnitLesson.search_text(s, IS_ERROR)
                ]