DofMap::add_constraint_row(): assert there is no diagonal entry
DofMap::add_constraint_row(): assert there is no diagonal entry

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