- remove unused code
  + getTypes_legacy method was no longer called
- fix the message for the init argument hash presence
  + the log facility is a singleton and is no longer passed
    as argument, thus the initialization hash argument
    is always expected as the first argument.
- added 'skipit' to the list of supported archs. I'm a bit unhappy
  with this change but I didn't see a better way to fix the arch
  check. In fact 'skipit' is not an architecture but for product
  building this architecture flag is used to indicate noarch rpm
  packages. In kiwi we check all arch values by one function
  KIWIXMLFileData::__isSupportedArch(), thus 'skipit' needs to be
  part of the list. The more clean fix would be to have two
  arch checking functions one for image building (real arch check)
  and one for product building (DVD source media). In order to
  keep the risk of regressions low I decided for the fast and
  easy way but we should have in mind that we can do better here.