WebYaST is broken after updating a Sentinel appliance to 7.3.0.1

After applying the 7.3.0.1 upgrade on an appliance, webyast fails to load with the following:

"There was an error in your Gemfile, and Bundler cannot continue.
chmod: cannot access /srv/www/webyast/Gemfile.lock
no such file or directory"

Resolution:

1. Edit the file /srv/www/webyast/Gemfile
2. At the top of the file, add the following:

     require 'yaml'

3. Save the file
4. Restart WebYaST

This problem is due to the updated version of
rubygem-bundler-1.7.0-0.7.1-x86_64.rpm.