Description of problem:
Using TestCaseRun.attach_bug verb I am getting an error:

NameError: global name 'trc' is not defined

I think there is a typo in testcaserun.py code (should be "tcr").
I am using the stage server at https://tcms-stage.englab.bne.redhat.com/xmlrpc/

Steps to Reproduce:
1. nitrate.do_command("TestCaseRun.attach_bug", [{"case_run_id": 475406, "bug_id": 690069, "bug_system_id": 1, "summary": "test", "description": "test"}])
  
Actual results:
See additional info

Expected results:
Should attach the bug info to the TestCaseRun

Additional info:
<?xml version='1.0'?>
<methodResponse>
<fault>
<value><struct>
<member>
<name>faultCode</name>
<value><int>1</int></value>
</member>
<member>
<name>faultString</name>
<value><string>Traceback (most recent call last):
  File "/usr/lib/python2.4/site-packages/kobo/django/xmlrpc/dispatcher.py", line 94, in _marshaled_dispatch
    response = self._dispatch(method, params)
  File "/usr/lib64/python2.4/SimpleXMLRPCServer.py", line 406, in _dispatch
    return func(*params)
  File "/usr/lib/python2.4/site-packages/kobo/django/xmlrpc/decorators.py", line 91, in _new_function
    return function(request, *args, **kwargs)
  File "/usr/lib/python2.4/site-packages/kobo/django/xmlrpc/decorators.py", line 31, in _new_func
    return func(request, *args, **kwargs)
  File "/usr/lib/python2.4/site-packages/tcms/xmlrpc/testcaserun.py", line 147, in attach_bug
    trc.add_bug(
NameError: global name 'trc' is not defined
Frame attach_bug in /usr/lib/python2.4/site-packages/tcms/xmlrpc/testcaserun.py at line 147
&lt;CODE&gt;
     140         try:
     141             bug_system = TestCaseBugSystem.objects.get(id = value['bug_system_id'])
     142         except:
     143             raise
     144         
     145         try:
     146             tcr = TestCaseRun.objects.get(case_run_id = value['case_run_id'])
--&gt;  147             trc.add_bug(
     148                 bug_id = value['bug_id'],
     149                 bug_system = bug_system,
     150                 summary = value.get('summary'),
     151                 description = value.get('description')
     152             )
     153         except: