e2fsck: always submit logical block 0 of a directory for pass 2

e2fsck: always submit logical block 0 of a directory for pass 2

Always iterate logical block 0 in a directory, even if no physical
block has been allocated.  Pass 2 will notice the lack of mapping and
offer to allocate a new directory block; this enables us to link the
directory into lost+found.

Previously, if there were no logical blocks mapped, we would fail to
pick up even block 0 of the directory for processing in pass 2.  This
meant that e2fsck never allocated a block 0 and therefore wouldn't fix
the missing . and .. entries for the directory; subsequent e2fsck runs
would complain about (yet never fix) the problem.

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