fix confusion between Tools::GetDeviceMapping() and Core::GetDeviceMapping() (bnc #858268)
version 0.801
Merge pull request #21 from WenhuaChang/master

cleanup errors messages during installation
added workaround to avoid double rootflags entry (bnc #858853)
fix checking wrong grub2-editenv path

fix checking wrong grub2-editenv path, it's not executed at all and
caused default menu entry not determined. (bnc#861469)