host: suppress double memory clear

HostFree() is calling HostClearMemory() so calling HostClearMemory()
before HostFree() is useless.

src/host.c

@@ -266,7 +266,6 @@ void HostShutdown(void)
             Host *h = host_hash[u].head;
             while (h) {
                 Host *n = h->hnext;
-                HostClearMemory(h);
                 HostFree(h);
                 h = n;
             }