We no longer allow (or need) null elemlinks
We no longer allow (or need) null elemlinks

clang-tidy caught this, when it wondered why we might be considering
calling parent() if we hadn't yet allocated space for a parent pointer.

jwpeterson/libmesh,dschwen/libmesh,jwpeterson/libmesh,libMesh/libmesh,jwpeterson/libmesh,dschwen/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,libMesh/libmesh,jwpeterson/libmesh,dschwen/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,libMesh/libmesh,dschwen/libmesh,dschwen/libmesh,libMesh/libmesh,libMesh/libmesh,libMesh/libmesh,dschwen/libmesh,libMesh/libmesh,dschwen/libmesh,dschwen/libmesh,libMesh/libmesh