engine: no documentation message

- Fixed issue where the locale in the links would have
  an underscore, while the documentation would contain
  a dash. This caused the message to popup even though
  the documentation was installed. Fixed it so it no longer
  matters if the link has an underscore or dash in it,
  both will correctly determine if the language is available.

Change-Id: Ic70eb10eb0264857568028f8307df4408dd36922
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1011430
Signed-off-by: Alexander Wels <awels@redhat.com>