verity_utils: always pass depth of 0

We deprecating passing a non-zero depth value.

BUG=chromium-os:9752
TEST=Ran the test.

Change-Id: Ifecef8d9af118de70b018abf58d95f90b189db6c

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

Review URL: http://codereview.chromium.org/6813027
1 file changed