Description of problem:
If you try to get task info for task which has no resource allocated, it fails with exception:
  xmlrpclib.Fault: <Fault 1: "<type 'exceptions.AttributeError'>:'NoneType' object has no attribute 'fqdn'">

------
import xmlrpclib
s = xmlrpclib.ServerProxy('https://beaker/RPC2')
print s.taskactions.task_info('T:17370872')
------

And I get following in server logs:
------------------------------------
Nov 20 15:14:21 light beaker-server[27448]: bkr.server.xmlrpccontroller ERROR Error handling XML-RPC method
Nov 20 15:14:21 light beaker-server[27448]:  Traceback (most recent call last):
Nov 20 15:14:21 light beaker-server[27448]:    File "/usr/lib/python2.6/site-packages/bkr/server/xmlrpccontroller.py", line 54, in RPC2
Nov 20 15:14:21 light beaker-server[27448]:      response = self.process_rpc(method,params)
Nov 20 15:14:21 light beaker-server[27448]:    File "/usr/lib/python2.6/site-packages/bkr/server/xmlrpccontroller.py", line 43, in process_rpc
Nov 20 15:14:21 light beaker-server[27448]:      response = obj(*params)
Nov 20 15:14:21 light beaker-server[27448]:    File "/usr/lib/python2.6/site-packages/bkr/server/task_actions.py", line 50, in task_info
Nov 20 15:14:21 light beaker-server[27448]:      return TaskBase.get_by_t_id(taskid).task_info()
Nov 20 15:14:21 light beaker-server[27448]:    File "/usr/lib/python2.6/site-packages/bkr/server/model.py", line 6275, in task_info
Nov 20 15:14:21 light beaker-server[27448]:      worker          = dict(name = self.recipe.resource.fqdn),
Nov 20 15:14:21 light beaker-server[27448]:  AttributeError: 'NoneType' object has no attribute 'fqdn'

Version-Release number of selected component (if applicable):
0.14.3

How reproducible:
100%

Steps to Reproduce:
1. call taskactions.task_info() on task, where recipe aborted or was cancelled before any system/resource was assigned to it

Actual results:
xml/rpc failure

Expected results:
xml/rpc works and returns state info

Additional info: