Commit 6f0be40dffe59bd9768a90525acf6166e566effb coming from bug 473696
changed the behavior of the getAffectedProjects() so that it returns now
also feature (non-Java!) projects. This breaks PDESourcePathProvider
which tries to create and resolve Java projects (resulting in Java Model
Exception for feature projects). To avoid this, make sure the new code
adding features to the affected projects list is not used from
PDESourcePathProvider.computeUnresolvedClasspath().

Change-Id: Ifb7aea0ea3621ebe82142736e18ccde7546248be
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>