The use of the PURIFY macro in ssleay_rand_bytes() is sufficient to

resolve the Valgrind issue with random numbers. Undo the changes to
RAND_bytes() and RAND_pseudo_bytes() that are redundant in this
respect.
Update documentation and FAQ accordingly, as the PURIFY macro is
available at least since 0.9.7.

crypto/rand/rand_lib.c

@@ -154,9 +154,6 @@ void RAND_add(const void *buf, int num, double entropy)
 int RAND_bytes(unsigned char *buf, int num)
 	{
 	const RAND_METHOD *meth = RAND_get_rand_method();
-#ifdef PURIFY
-	memset(buf, 0, num);
-#endif
 	if (meth && meth->bytes)
 		return meth->bytes(buf,num);
 	return(-1);
@@ -165,9 +162,6 @@ int RAND_bytes(unsigned char *buf, int num)
 int RAND_pseudo_bytes(unsigned char *buf, int num)
 	{
 	const RAND_METHOD *meth = RAND_get_rand_method();
-#ifdef PURIFY
-	memset(buf, 0, num);
-#endif
 	if (meth && meth->pseudorand)
 		return meth->pseudorand(buf,num);
 	return(-1);