title: Mongodb createUser Exception
body: <p>I'm using mongodb version 2.6.7 and getting following error.   </p>
  
  <pre><code>&gt; use admin
      switched to db admin
      &gt; db.version();
      2.6.7
      &gt; db.createUser({user: 'root', pwd: 'r00t', roles: [{role: 'readWrite', db: 'metadata_repo'}]});
      Tue Nov  3 18:43:06.765 JavaScript execution failed: TypeError: Property 'createUser' of object admin is not a function
      &gt;
  </code></pre>
  
  <p>I'm connecting to mongod server from localhost with mongodb 2.4.5 shell. Can this affect?</p>