[PATCH] jbd: log_do_checkpoint fix

While checkpointing we have to check that our transaction still is in the
checkpoint list *and* (not or) that it's not just a different transaction
with the same address.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>