When all target platforms are resolved, projects from the
eclipse.platform.swt.binaries repo are imported but they have errors.
Change the source locator to exclude all platform-specific projects and
then include only the one project for the current specific platform.

Change-Id: Ic1d6e1fa08fff77846dfb9027ffb74c7f90ed11a
Signed-off-by: Ed Merks <ed.merks@gmail.com>