Exception in ubuntu-bug after update to python 2.7

Binary package hint: apport

Exception occurs in ubuntu-bug (apport 1.16-0ubuntu1) after update to python 2.7 (python 2.7.1-0ubuntu1)

$ ubuntu-bug gwibber

*** Collecting problem information

The collected information can be sent to the developers to improve the
application. This might take a few minutes.
.....
Traceback (most recent call last):
  File "/usr/bin/apport-cli", line 414, in <module>
    if not app.run_argv():
  File "/usr/lib/python2.7/dist-packages/apport/ui.py", line 563, in run_argv
    return self.run_report_bug()
  File "/usr/lib/python2.7/dist-packages/apport/ui.py", line 413, in run_report_bug
    response = self.ui_present_report_details(False)
  File "/usr/bin/apport-cli", line 236, in ui_present_report_details
    self.format_filesize(self.get_complete_size()))
  File "/usr/lib/python2.7/dist-packages/apport/ui.py", line 701, in format_filesize
    return locale.format('%.1f KiB', size/1024.)
  File "/usr/lib/python2.7/locale.py", line 189, in format
    "format specifier, %s not valid") % repr(percent))
ValueError: format() must be given exactly one %char format specifier, '%.1f KiB' not valid