Description of Problem:
A problem exists where php3 is always installed on an upgrade due to the logic
"if an optional package P exists in the sfx where the group matches a package Q
which is already upgraded, always install the package P."

Steps to Reproduce:
1. Install without php3
2. Upgrade existing installation

Actual Results:
Not prompted for selection of php3 package.

Expected Results:
php3 should be listed in optional package selection.

Additional Information:
Suggested correct fix is to:
- abandon optional package groups based on the Group field
- change catapult to loop resolving dependencies based on suggestedPackages,
as update-agent does