Backport r58757, r58758, r58759.

Backport r58757, r58758, r58759.
Undoes incorrect dbtables fix and errant strdup introduced as
described below:

r58757 | gregory.p.smith | 2007-11-01 14:08:14 -0700 (Thu, 01 Nov 2007) | 4 lines

Fix bug introduced in revision 58385.  Database keys could no longer
have NULL bytes in them.  Replace the errant strdup with a
malloc+memcpy.  Adds a unit test for the correct behavior.

r58758 | gregory.p.smith | 2007-11-01 14:15:36 -0700 (Thu, 01 Nov 2007) | 3 lines

Undo revision 58533 58534 fixes.  Those were a workaround for
a problem introduced by 58385.

r58759 | gregory.p.smith | 2007-11-01 14:17:47 -0700 (Thu, 01 Nov 2007) | 2 lines

false "fix" undone as correct problem was found and fixed.