make sure that the C++ name normalization method does not strip leading :: unnecessarily
make sure that the C++ name normalization method does not strip leading :: unnecessarily

This fixes a bug in which types with a 'base' namespace, when used
in templates (vectors, smart pointers), resolve to RTT::base in
the CORBA transport. This happens since we have to specialize
a template in the CORBA transport, and thus do it in the RTT::
namespace

doudou/modelkit-component,doudou/modelkit-component