Traceback (most recent call last):
  File "/usr/sbin/update-apt-xapian-index", line 108, in <module>
    indexer.rebuild(opts.pkgfile)
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 758, in rebuild
    cleanoldcaches(axi.XAPIANCACHEPATH)
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 756, in cleanoldcaches
    shutil.rmtree(fullpath)
  File "/usr/lib/python2.7/shutil.py", line 250, in rmtree
    onerror(os.remove, fullname, sys.exc_info())
  File "/usr/lib/python2.7/shutil.py", line 248, in rmtree
    os.remove(fullname)
OSError: [Errno 5] Input/output error: '/var/cache/apt-xapian-index/index.1/synonym.baseB'