When we first encountered this exception, we didn't found any solution except just to do fresh check-out from SVN. After fresh check-out, application was running perfectly - strange things happen, there is always some magic ;-)
Later we found real cause for this deployment exception. We found solution as well, but still we didn't found exact scenario how to reproduce it in sample application, if you know scenario - feel free to post in comments. Now I will describe the reason and solution for this exception.
Exception happens, because for some unknown reasons, JDeveloper 11g IDE in very rare cases generates ViewController files in Model project:
This happens automatically, even when developer is not doing any work in Model. And then during deployment, WLS finds ViewController files in Model. And since Model don't have appropriate JAR libraries on class path (for absolutely logical reasons), it throws exception about javax.faces.webapp.FacesServlet not found:
In order to fix this exception, just go to file system and remove public_html folder from Model project:
Now go to your Model project, refresh it - not needed Web Content is gone:
When Web Content is removed from Model, you are ready to deploy and run your application again.