Make localIndexMap_ a non-empty list of indices of interior elements.

Judging from ParallelDebugOutput.hh this is what is should be.
Before this commit it was empty as it had space reserved but never
any entries pushed (they were inserted with operator[]).

ebos/collecttoiorank.hh

@@ -250,7 +250,7 @@ namespace Ewoms
                     // only store interior element for collection
                     if( element.partitionType() == Dune :: InteriorEntity )
                     {
-                        localIndexMap_[elemIdx] = elemIdx;
+                        localIndexMap_.push_back( elemIdx );
                     }
                 }