[PATCH] ext3 balloc: fix off-by-one against rsv_end

rsv_end is the last block within the reservation, so alloc_new_reservation
should accept start_block == rsv_end as success.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>