Move MatrixBlock specializations inside namespace.

This is necessary since the calls are ns-qualified in the
matrix market code.

opm/simulators/linalg/MatrixMarketSpecializations.hpp

@@ -44,8 +44,6 @@ namespace MatrixMarketImpl
         }
     };
 
-} // namespace MatrixMarketImpl
-
     template<class M>
     struct mm_multipliers;
 
@@ -58,6 +56,9 @@ struct mm_multipliers<BCRSMatrix<Opm::MatrixBlock<T,i,j>, A>>
         };
     };
 
+} // namespace MatrixMarketImpl
+
+
 } // namespace Dune
 
 #endif