opencryptoki: Fix to opencryptoki PKCS#11 TPM generated key handling

Original patch by Nelson Araujo <nelsona@chromium.org>.
http://codereview.chromium.org/5179001

BUG=chromium-os:14440
TEST=none

Change-Id: Icfec6716cb25268d9fbf008d7104017782f0945c
1 file changed