Top level facets are not detected as installed even though subtype facets are installed

The invocation project.getFacet(ServletFacet.class) returns null event though the project has the Servlet 3.0 facet associated with it.

This requires explicit invocations like project.getFacet(ServletFacet_3_0.class), project.getFacet(ServletFacet_3_1.class) etc.

This also affects other top-level facets like the CDI and EJB facets.