- when rewriting sources.list, transition the commercial
    package archive to the new location
* DistUpgrade/DistUpgradeCache.py:
  - fix bogus log messages about missing "required" priority packages
* DistUpgrade/DistUpgradeViewGtk.py:
  - remove debug messages
* DistUpgrade/DistUpgrade.cfg:
  - remove gnome-cups-manager on upgrade, system-config-printer 
    replaces it (LP: #107766)
  - set cursor to the start of the details list (LP: #134873)
* DistUpgrade/dist-upgrade.py, DistUpgrade/DistUpgradeViewText.py,
  DistUpgrade/DistUpgradeViewKDE.py, DistUpgrade/DistUpgradeViewGtk.py:
  - make logdir a config option too
* tests/test_sources_list.py, tests/data-sources-list-test:
  - added tests for sources.list rewriting