CXF Blueprint namespace don't work well with blueprint-core 1.7.x

Aries blueprint-core 1.7.1 changes (improves) the way namespace handlers (classes implementing org.apache.aries.blueprint.NamespaceHandler interface) resolve namespaces to URIs.

The problem is when XSD behind a handler imports other XSDs that may be resolved by other handlers.

Around Aries blueprint-core 1.4.x, imported XSDs where looked up in all currently registered handlers, but this was prone to race conditions, because handler that could resolve given imported XSD might've not been registered yet.

The clean solution is to delegate at code level to correct handler.