verity: don't error on depth=0

verity: don't error on depth=0

Support for depth=0 (i.e. compute depth) was added as part of:

commit 8019a6a4fdc022430376e270cdcc2b19113527c8
Author: Mandeep Singh Baines <msb@chromium.org>;
Date:   Fri Apr 1 15:07:39 2011 -0700

    verity: create a regular trie when depth=0

BUG=9752
TEST=Ran dm-verity.git unit tests. Ran platform_DMVerityCorruption on H/W.

Change-Id: Ie5ecaf8c8bb0e06e80edb9bad3170dc14d0983c2

R=wad@chromium.org,taysom@chromium.org,ups@chromium.org

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=e8dbf3e

[Will Drewry, 2011-04-07 01:22:57]

LGTM

[Will Drewry, 2011-04-07 01:23:47]

+extra people who should be aware of these changes :)

[Paul T, 2011-04-07 15:46:35]

LGTM