BUG-CF-000213 removing a few packages from the purge list

It was reported that too many packages were being purged by the following script.

https://github.com/intalio/vcap/blob/java_start/dev_setup/bin/vcap_stop_for_export.sh

Apparently CF admin upgrade had some issues, and the following packages needed to be installed:

g++ make ruby1.8-dev libxslt-dev libxml2-dev libpq-dev

To fix this problem, we need to remove those packages and their dependencies form the list of purged packages.