Fix the Eclipse PDE Target Platform droplet bundle detection.

Before this change, any bundle from a droplet location (most bundles now) would not show up as part of the default target platform (generated from existing eclipse rpm bundles). This should be fixed now, and bundles within droplets should show up as part of the PDE target platform.

If already using a PDE target platform, it may be necessary to re-generate it from the 'default' option to see the changes.