[release,parallel] Allow copying of RemoteIndexListModifier.

Previously, copying a RemoteIndexListModifier resulted in a double
free of a pointer to a list of global indices. There was no need to
use a pointer to this, though. After this patch we store the list directly
by value. Thus the default copy constructor works but makes a rather cheap copy
of a (most often empty) singly linked list and we get rid off the non-default
destructor.

dune/common/parallel/remoteindices.hh

@@ -674,13 +674,6 @@ namespace Dune {
       : glist_()
     {}
 
-    /** @brief Constructor */
-    ~RemoteIndexListModifier()
-    {
-      if(glist_)
-        delete glist_;
-    }
-
   private:
 
     /**
@@ -1560,13 +1553,13 @@ namespace Dune {
   template<class T, class A, bool mode>
   RemoteIndexListModifier<T,A,mode>::RemoteIndexListModifier(const ParallelIndexSet& indexSet,
                                                              RemoteIndexList& rList)
-    : rList_(&rList), indexSet_(&indexSet), glist_(new GlobalList()), iter_(rList.beginModify()), end_(rList.end()), first_(true)
+    : rList_(&rList), indexSet_(&indexSet), iter_(rList.beginModify()), end_(rList.end()), first_(true)
   {
     if(MODIFYINDEXSET) {
       assert(indexSet_);
       for(ConstIterator iter=iter_; iter != end_; ++iter)
-        glist_->push_back(iter->localIndexPair().global());
-      giter_ = glist_->beginModify();
+        glist_.push_back(iter->localIndexPair().global());
+      giter_ = glist_.beginModify();
     }
   }
 
@@ -1589,7 +1582,7 @@ namespace Dune {
       typedef typename ParallelIndexSet::const_iterator IndexIterator;
       typedef typename GlobalList::const_iterator GlobalIterator;
       typedef typename RemoteIndexList::iterator Iterator;
-      GlobalIterator giter = glist_->begin();
+      GlobalIterator giter = glist_.begin();
       IndexIterator index = indexSet_->begin();
 
       for(Iterator iter=rList_->begin(); iter != end_; ++iter) {