files /var/log/dist-upgrade/main.log and /var/log/dist-upgrade/apt.log

Traceback (most recent call last):

  File "/tmp/update-manager-GO5YGL/quantal", line 10, in <module>
    sys.exit(main())

  File "/tmp/update-manager-GO5YGL/DistUpgrade/DistUpgradeMain.py", line 237, in main
    save_system_state(logdir)

File "/tmp/update-manager-GO5YGL/DistUpgrade/DistUpgradeMain.py", line 130, in save_system_state
    scrub_sources=True)

  File "/tmp/update-manager-GO5YGL/DistUpgrade/apt_clone.py", line 146, in save_state
    self._write_state_installed_pkgs(sourcedir, tar)

  File "/tmp/update-manager-GO5YGL/DistUpgrade/apt_clone.py", line 173, in _write_state_installed_pkgs
    cache = self._cache_cls(rootdir=sourcedir)

  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 102, in __init__
    self.open(progress)

  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 149, in open
    self._list.read_main_list()

SystemError: E:Malformed line 3 in source list /etc/apt/sources.list (dist)