Make sure all of the fields of the group descriptor are properly
initialized.  Previously, we allowed bg_flags field to be contain
random garbage, which could trigger non-deterministic behavior,
including a kernel OOPS.

http://bugzilla.kernel.org/show_bug.cgi?id=12433Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org