Comment 41 for bug 1690980

So far this seems to work, I don't get an inconsistent system while testing on Ubuntu 16.04, I did notice a crash report in /var/crash from unattended-upgrades. Here's the Traceback:

 Traceback (most recent call last):
   File "/usr/bin/unattended-upgrade", line 918, in do_install
     cache, logfile_dpkg, options.verbose or options.debug)
   File "/usr/bin/unattended-upgrade", line 433, in upgrade_normal
     res, error = cache_commit(cache, logfile_dpkg, verbose)
   File "/usr/bin/unattended-upgrade", line 424, in cache_commit
     res = cache.commit(install_progress=iprogress)
   File "/usr/lib/python3/dist-packages/apt/cache.py", line 515, in commit
     res = self.install_archives(pm, install_progress)
   File "/usr/lib/python3/dist-packages/apt/cache.py", line 479, in install_archives
     res = install_progress.run(pm)
   File "/usr/lib/python3/dist-packages/apt/progress/base.py", line 208, in run
     res = self.wait_child()
   File "/usr/lib/python3/dist-packages/apt/progress/base.py", line 279, in wait_child
     self.update_interface()
   File "/usr/bin/unattended-upgrade", line 227, in update_interface
     self._do_verbose_output_if_needed()
   File "/usr/bin/unattended-upgrade", line 244, in _do_verbose_output_if_needed
     os.write(1, os.read(self.output_logfd, 1024))
 OSError: [Errno 5] Input/output error

 During handling of the above exception, another exception occurred:

 Traceback (most recent call last):
   File "/usr/bin/unattended-upgrade", line 1581, in <module>
     main(options)
   File "/usr/bin/unattended-upgrade", line 1468, in main
     logfile_dpkg)
   File "/usr/bin/unattended-upgrade", line 921, in do_install
     os.write(2, ("Exception: %s\n" % e).encode('utf-8'))
 OSError: [Errno 5] Input/output error