Comment 2 for bug 1030498

In UbiquitySyslog.txt:

Jul 29 10:52:40 ubuntu plugininstall.py: Traceback (most recent call last):
Jul 29 10:52:40 ubuntu plugininstall.py: File "/usr/lib/ubiquity/ubiquity/install_misc.py", line 923, in do_install
Jul 29 10:52:40 ubuntu plugininstall.py: fetchprogress, installprogress):
Jul 29 10:52:40 ubuntu plugininstall.py: File "/usr/lib/ubiquity/ubiquity/install_misc.py", line 809, in commit_with_verify
Jul 29 10:52:40 ubuntu plugininstall.py: res = cache._fetch_archives(fetcher, pm)
Jul 29 10:52:40 ubuntu plugininstall.py: File "/usr/lib/python3/dist-packages/apt/cache.py", line 304, in _fetch_archives
Jul 29 10:52:40 ubuntu plugininstall.py: return self._run_fetcher(fetcher)
Jul 29 10:52:40 ubuntu plugininstall.py: File "/usr/lib/python3/dist-packages/apt/cache.py", line 286, in _run_fetcher
Jul 29 10:52:40 ubuntu plugininstall.py: raise FetchFailedException(err_msg)
Jul 29 10:52:40 ubuntu plugininstall.py: apt.cache.FetchFailedException: Failed to fetch http://cn.archive.ubuntu.com/ubuntu/pool/main/f/firefox/firefox-locale-en_15.0~b1+build1-0ubuntu1_amd64.deb 404 Not Found
Jul 29 10:52:40 ubuntu plugininstall.py:
Jul 29 10:52:40 ubuntu plugininstall.py:
Jul 29 10:52:40 ubuntu plugininstall.py: log-output -t ubiquity chroot /target umount /sys
Jul 29 10:52:40 ubuntu plugininstall.py: log-output -t ubiquity chroot /target umount /proc
Jul 29 10:52:40 ubuntu plugininstall.py: log-output -t ubiquity umount /target/dev
Jul 29 10:52:40 ubuntu plugininstall.py: log-output -t ubiquity umount /target/cdrom
Jul 29 10:52:40 ubuntu finish-install: Disabling CD in sources.list