examples: fix demo button in leiningen example

examples/leiningen/resources/public/demo.html

@@ -12,6 +12,6 @@ <h1>Dirac DevTools Demo Project</h1>
   <a href="https://github.com/binaryage/dirac">Dirac DevTools</a> provides a custom DevTools frontend packaged in a Chrome Extension.<br>
   To use REPL from Dirac you also need to start an nREPL server and a Dirac Agent server.<br>
 </p>
-<button onclick="dirac_sample.demo.breakpoint_demo_handler()">demo a breakpoint!</button>
+<button onclick="dirac_lein.demo.breakpoint_demo_handler()">demo a breakpoint!</button>
 </body>
 </html>