qannotate <File> from lightweight checkout crashes

[Craig Hewetson]

Run qannotate on a single within a lightweight checkout.... the dialog appears but then crashes:

bzr qannotate src/AWS/EventBrokerPlugin/src/com/blah/ngmc/rcp/eventbroker/data/TopicLabelProvider.java
bzr: ERROR: exceptions.ValueError: key u'current:/home/craig/projects/blah/ngmc/release/v4.5' not a plain string

Traceback (most recent call last):
  File "/home/craig/.bazaar/plugins/qbzr/lib/trace.py", line 300, in reports_exception_decorate
    return f(*args, **kargs)
  File "/home/craig/.bazaar/plugins/qbzr/lib/annotate.py", line 400, in initial_load
    self.annotate(self.annotate_tree, self.fileId, self.path)
  File "/home/craig/.bazaar/plugins/qbzr/lib/annotate.py", line 482, in annotate
    logmodel.WithWorkingTreeGraphVizLoader)
  File "/home/craig/.bazaar/plugins/qbzr/lib/logwidget.py", line 101, in load
    self.log_model.load(*args, **kargs)
  File "/home/craig/.bazaar/plugins/qbzr/lib/logmodel.py", line 163, in load
    graph_viz.load()
  File "/home/craig/.bazaar/plugins/qbzr/lib/logmodel.py", line 99, in load
    super(GraphVizLoader, self).load()
  File "/home/craig/.bazaar/plugins/qbzr/lib/loggraphviz.py", line 207, in load
    self.compute_head_info()
  File "/home/craig/.bazaar/plugins/qbzr/lib/loggraphviz.py", line 607, in compute_head_info
    in self.graph.find_unique_ancestors(revid, other_revids) \
  File "/usr/lib/python2.6/dist-packages/bzrlib/graph.py", line 372, in find_unique_ancestors
    [unique_revision], common_revisions)
  File "/usr/lib/python2.6/dist-packages/bzrlib/graph.py", line 407, in _find_initial_unique_nodes
    next_unique_nodes = set(unique_searcher.step())
  File "/usr/lib/python2.6/dist-packages/bzrlib/graph.py", line 1257, in step
    return self.next()
  File "/usr/lib/python2.6/dist-packages/bzrlib/graph.py", line 1279, in next
    self._advance()
  File "/usr/lib/python2.6/dist-packages/bzrlib/graph.py", line 1313, in _advance
    found, ghosts, next, parents = self._do_query(self._next_query)
  File "/usr/lib/python2.6/dist-packages/bzrlib/graph.py", line 1336, in _do_query
    parent_map = self._parents_provider.get_parent_map(revisions)
  File "/usr/lib/python2.6/dist-packages/bzrlib/graph.py", line 99, in get_parent_map
    new_found = parents_provider.get_parent_map(remaining)
  File "/usr/lib/python2.6/dist-packages/bzrlib/graph.py", line 167, in get_parent_map
    parent_map = self._get_parent_map(needed_revisions)
  File "/usr/lib/python2.6/dist-packages/bzrlib/remote.py", line 1495, in _get_parent_map_rpc
    "key %r not a plain string" % (key,))
ValueError: key u'current:/home/craig/projects/blah/ngmc/release/v4.5' not a plain string

Running latest from trunk:
qbzr 0.20.0dev1