Clarify BoundaryInfo::operator= comment
Clarify BoundaryInfo::operator= comment

dschwen/libmesh,jwpeterson/libmesh,libMesh/libmesh,dschwen/libmesh,libMesh/libmesh,dschwen/libmesh,roystgnr/libmesh,libMesh/libmesh,dschwen/libmesh,roystgnr/libmesh,roystgnr/libmesh,jwpeterson/libmesh,dschwen/libmesh,roystgnr/libmesh,dschwen/libmesh,roystgnr/libmesh,roystgnr/libmesh,libMesh/libmesh,BalticPinguin/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,libMesh/libmesh,dschwen/libmesh,jwpeterson/libmesh,roystgnr/libmesh,dschwen/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,libMesh/libmesh,BalticPinguin/libmesh,BalticPinguin/libmesh,roystgnr/libmesh,libMesh/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,libMesh/libmesh