SpringBus.getId() may fail to determine the symbolic bundle name

SpringBus.getId() should use reflection over public interface to get the bundle symbolic name

This method currently uses reflection on the bundle context implementation class (and this could be org.apache.felix.framework.BundleContextImpl) and this may lead to the illegal access exception:

java.lang.IllegalAccessException: Class org.apache.cxf.bus.spring.SpringBus can not access a member of class org.apache.felix.framework.BundleContextImpl with modifiers "public"

This will result in not retrieving the symbolic name that could be otherwise retrieved.

I am modifying the SpringBus to use the org.osgi.framework.* interfaces to do the invocation to avoid this issue.