bzr: ERROR: Could not parse --commit-time: unconverted data remains: .000000000

Bazaar can't parse time when fraction of seconds is specified. Numerous tools output time in this format and their documentation even sometimes calls this an ISO format (e.g. ls --style=full-iso). It looks like recent python can parse such time without problems:
http://stackoverflow.com/questions/698223/how-can-i-parse-a-time-string-containing-milliseconds-in-it-with-python

$ bzr --version
Bazaar (bzr) 2.3.1
  Python interpreter: /usr/bin/python 2.7.1
  Python standard library: /usr/lib/python2.7
  Platform: Linux-2.6.38-8-generic-x86_64-with-Ubuntu-11.04-natty

$ /usr/bin/stat --format %y some_file
2011-06-26 15:27:16.000000000 +0300

$ bzr commit --commit-time="$(stat --format %y some_file)"
bzr: ERROR: Could not parse --commit-time: unconverted data remains: .000000000