Update the templates and configuration files to support grub2 live
image creation.
Related: rhbz#1102318
Related: rhbz#1131199
(cherry picked from commit da8326fd58)
live media isn't exactly the same as the Anaconda install media. Right
now this amounts to needing a root= cmdline argument but in the future
there may be other differences.
This also reverts 5437557846 on the new copies of the templates.