Use existing BoundaryInfo::BCTuple in a couple more places
Use existing BoundaryInfo::BCTuple in a couple more places

This was already being done correctly in the .C file, so only the .h
file needed updating.

libMesh/libmesh,libMesh/libmesh,libMesh/libmesh,libMesh/libmesh,libMesh/libmesh,libMesh/libmesh,libMesh/libmesh,libMesh/libmesh