gcc-4.3 c++ question

[Neal Becker]

On upgrading from gcc-4.1.2 to gcc-4.3, this (stripped down) code is now
rejected:

#include <vector>
#include <iostream>

template<typename T, template <typename A> class CONT=std::vector>
class Ring {

};


template<typename Cont>
inline std::ostream& operator<<(std::ostream& os, const Ring<Cont>& r) {
  os << '[';
  os << ']';
  return os;
}
g++ -c test1.cc
test1.cc:11: error: type/value mismatch at argument 2 in template parameter
list for  template<class T, template<class A> class CONT> class Ring 
test1.cc:11: error:   expected a template of type  template<class A> class
CONT , got  template<class _Tp, class _Alloc> class std::vector 

What is a reasonable way to fix this?  The problem is that the 2nd parameter
says 

template<typename A> class CONT, which doesn't match std::vector because it
has an _optional_ 2nd parameter (class _Alloc).

I don't want to only match class CONT with those having a 2nd parameter
(class _Alloc) - that is too restrictive.