participant status is more useful than participant role in campaign profile

This change affects the Update Event Invite Responses created when you enable the civicrm_engage Drupal module.

Based on conversations with PTP users we don't think the participant role field should be included - only participant status. This will only affect new installs moving forward and even then, it will only impact the default profile created for you (which you can later modify).

I'm committing to head so it goes into 4.3.