Still vulnerable to Heartbleed after updating and reboot

Question

I'm on Ubuntu 12.04, I have updated openssl with the latest update :

$ openssl version -a
OpenSSL 1.0.1 14 Mar 2012
built on: Mon Apr  7 20:33:29 UTC 2014

And also updated libssl

$ sudo apt-get install libssl1.0.0
Reading package lists... Done
Building dependency tree       
Reading state information... Done
libssl1.0.0 is already the newest version.

Then I rebooted the server but still show vulnerability using http://filippo.io/Heartbleed. Any ideas? Thanks.