bug fixed: when inited=0, can_be_used should be 0 too. (BUG#4901)

mysys/mf_keycache.c:
  bug fixed: when inited=0, can_be_used should be 0 too. (BUG#4901)
  end spaces removed (no merge problems as this file doesn't change much)

mysys/mf_keycache.c

@@ -625,7 +625,7 @@ writes: %ld  r_requests: %ld  reads: %ld",
   if (cleanup)
   {
     pthread_mutex_destroy(&keycache->cache_lock);
-    keycache->key_cache_inited= 0;
+    keycache->key_cache_inited= keycache->can_be_used= 0;
     KEYCACHE_DEBUG_CLOSE;
   }
   DBUG_VOID_RETURN;