Drop grub1

![Warning](https://raw.githubusercontent.com/yast/yast-theme/master/icons/hicolor/32x32/apps/msg_warning.png) **NOTE: merge this after creating the maintenance branch for SLE-12 and after switching Jenkins to use the new branch**
well, I think location for sure not. In fact whole this section managent will be removed, but now it is too tight, so to avoid breakage I kept it here.