F16 Alpha GRUB install failure

[Michael Schwendt]

Between TC1 and release of F16 Alpha, something must have changed to the
worse with regard to installing GRUB to a partition's primary sector.
Partitioning hasn't changed. TC1 managed to install GRUB to /dev/sda3.
Anaconda now reports failure to install, and I've found this on virtual
console:

  /usr/sbin/grub2-setup: warn: Attempting to install GRUB to a
  partitionless disk or to a partitionj. This is a BAD idea..

  /usr/sbin/grub2-setup: warn: Embedding is not possible. GRUB can only be
  installed in this setup using blocklists. However, blocklists are
  UNRELIABLE and their use is discouraged..

  /usr/sbin/grub2-setup: error: will not proceed with blocklists.

Bug or feature?