Fix predicted first rand() call

sql/sql_class.cc:
  Fix Random hash initialization on for new connections to make result
  it more random

sql/sql_class.cc

@@ -156,7 +156,7 @@ THD::THD():user_time(0),fatal_error(0),last_insert_id_used(0),
   */
   {
     pthread_mutex_lock(&LOCK_thread_count);
-    ulong tmp=(ulong) (rnd(&sql_rand) * 3000000);
+    ulong tmp=(ulong) (rnd(&sql_rand) * 0xffffffff); /* make all bits random */
     pthread_mutex_unlock(&LOCK_thread_count);
     randominit(&rand, tmp + (ulong) &rand, tmp + (ulong) ::query_id);
   }