fts extension fails to load

The FTS extension fails to load if ZG is running and one executes `zeitgeist-daemon --replace`. It fails with this error:

DEBUG:zeitgeist.extension:Loading extension 'SearchEngineExtension'
DEBUG:zeitgeist.fts:Opening full text index: /home/miso/.local/share/zeitgeist/fts.index
ERROR:zeitgeist.extension:Failed loading the 'SearchEngineExtension' extension
Traceback (most recent call last):
  File "/usr/local/share/zeitgeist/_zeitgeist/engine/extension.py", line 247, in load
    obj = extension(self.__engine)
  File "/home/miso/.local/share/zeitgeist/extensions/fts.py", line 90, in __init__
    self._indexer = Indexer(self.engine)
  File "/home/miso/.local/share/zeitgeist/extensions/fts.py", line 132, in __init__
    self._index = xapian.WritableDatabase(INDEX_FILE, xapian.DB_CREATE_OR_OPEN)
  File "/usr/lib/python2.6/dist-packages/xapian.py", line 2886, in __init__
    _xapian.WritableDatabase_swiginit(self,_xapian.new_WritableDatabase(*args))
DatabaseLockError: Unable to acquire database write lock on /home/miso/.local/share/zeitgeist/fts.index: already locked