ECLIPSE-1011 - remove eclipse internal depenency for project selection i...

Referencing PackageFragmentRootContainer may cause a java.lang.NoClassDefFoundError: org/eclipse/jdt/internal/ui/packageview/PackageFragmentRootContainer.  This is an internal eclipse class (there were discouraged access warning assocaited with it as well).  

Replaced w/ project ref through the adapter if present.