e2fsck: fix minor errors in journal handling

e2fsck: fix minor errors in journal handling

The journal superblock's s_sequence field seems to track the tid of
the tail (oldest) transaction in the log.  Therefore, when we release
the journal, set the s_sequence to the tail_sequence, because setting
it to the transaction_sequence means that we're setting the tid to
that of the head of the log.  Granted, for replay these two are
usually the same (and s_start == 0 anyway) so thus far we've gotten
lucky and nobody noticed.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>