Fix bug in resize2fs which caused it to fail on filesystems with a

Fix bug in resize2fs which caused it to fail on filesystems with a
non-empty bad block list.  Resize2fs now discards any blocks on the
badblock list which are no longer part of the filesystem as the result
of a filesystem shrink.  (Note: this means that shrinking and then
enlarging a filesystem is no longer a reversible operation;
information about bad blocks in the part of the filesystem
which is to be chopped off will be lost.)