Make sure the rand_byte buffer in padlock engine is cleansed.

Submitted by Michael McConville <mmcco@mykolab.com>
Reviewed-by: NRich Salz <rsalz@openssl.org>

engines/e_padlock.c

@@ -776,7 +776,7 @@ static int padlock_rand_bytes(unsigned char *output, int count)
         *output++ = (unsigned char)buf;
         count--;
     }
-    *(volatile unsigned int *)&buf = 0;
+    OPENSSL_cleanse(&buf, sizeof(buf));
 
     return 1;
 }