correct string in error message

dune/gmsh4/gmsh4reader.impl.hh

@@ -287,7 +287,7 @@ void Gmsh4Reader<G,C,S>::read (std::string const& filename, bool fillCreator)
   } else if (ext == ".pro") {
     readParallelFileFromStream(input, comm().rank(), comm().size(), fillCreator);
   } else {
-    DUNE_THROW(IOError, "File has unknown file-extension '" << ext << "'. Allowed are only '.vtu' and '.pvtu'.");
+    DUNE_THROW(IOError, "File has unknown file-extension '" << ext << "'. Allowed are only '.msh' and '.pro'.");
   }
 }