[PATCH] jbd: Remove useless loop when writing commit record

Commit block was intended to have several copies of the header. But
due to a bug it never had them and actually, nobody checks that. So
just remove the useless loop.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>