e2fsck: try to salvage corrupt directory entry blocks

e2fsck: try to salvage corrupt directory entry blocks

Remove the code that would prompt the user to zap directory entry
blocks with bad checksums (i.e. strict_csums).  Instead, we'll run the
directory entries through the usual repair routines in an attempt to
save whatever we can.  At the same time, refactor the code that
schedules the repair of missing dirblock checksum entries.

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