Replace CollectiveCommunication by Communication

CollectiveCommunication has been deprecated, but nobody has bothered to do something about it. Now it is gone in the git master branch. Update the FoamGrid code accordingly.

dune/foamgrid/foamgrid.hh

@@ -580,7 +580,7 @@ public:
         {}
 
         /** dummy collective communication */
-        const typename Traits::CollectiveCommunication& comm () const
+        const typename Traits::Communication& comm () const
         {
             return ccobj_;
         }
@@ -687,7 +687,7 @@ public:
     }
 
     //! Collective communication interface
-    typename Traits::CollectiveCommunication ccobj_;
+    typename Traits::Communication ccobj_;
 
     template<std::size_t... dimEntity>
     static auto makeEntityImpsImpl_(std::index_sequence<dimEntity...>, std::size_t numLevels)