Bug in jffs2/scan.c re: incorrect assumption of "allclean"block

[Steven J. Magnani]

> Well, I've looked trough your debug output and the code and think the
following patch should fix the bug.

That also seems to work. I assume that the test for "jeb->used_size ==
PAD(c->cleanmarker_size)" assures that jeb->first_node is non-NULL, so
dereferencing it won't ever cause an oops.

Should the code at line 631 be changed to look more like your patched
code? (Why the difference?)

Steve