Description of problem:
bkr job-watch crashes if you tell it to watch a recipe (e.g. R:123) or a task (e.g. T:123).

Version-Release number of selected component (if applicable):
0.15

How reproducible:
always

Steps to Reproduce:
1. Run bkr job-watch R:123 or bkr job-watch T:123

Actual results:
Watching tasks (this may be safely interrupted)...
Traceback (most recent call last):
  File "/usr/bin/bkr", line 9, in <module>
    load_entry_point('bkr.client==0.15.2', 'console_scripts', 'bkr')()
  File "/usr/lib/python2.6/site-packages/bkr/client/main.py", line 58, in main
    return cmd.run(*cmd_args, **cmd_opts.__dict__)
  File "/usr/lib/python2.6/site-packages/bkr/client/commands/cmd_job_watch.py", line 87, in run
    sys.exit(watch_tasks(self.hub, args))
  File "/usr/lib/python2.6/site-packages/bkr/client/task_watcher.py", line 37, in watch_tasks
    changed |= watcher.update(task)
  File "/usr/lib/python2.6/site-packages/bkr/client/task_watcher.py", line 108, in update
    print "%s: %s" % (task, task.display_state(task.task_info))
  File "/usr/lib/python2.6/site-packages/bkr/client/task_watcher.py", line 142, in display_state
    return "%s (%s)" % (task_info["state_label"], worker["name"])
KeyError: 'name'

Expected results:
Should watch the given recipe or task.

Additional info:
Watching a job or recipeset works correctly.