Bug 920899: Fix bad memset in hmac_test. r=wtc.
Bug 920899: Fix bad memset in hmac_test. r=wtc.

nmav/nss,nmav/nss,nmav/nss,ekr/nss-old,ekr/nss-old,ekr/nss-old,ekr/nss-old,ekr/nss-old,nmav/nss,nmav/nss,nmav/nss,nmav/nss,ekr/nss-old,ekr/nss-old