update called fn name in flow_routing_D8.py
update called fn name in flow_routing_D8.py

RondaStrauch/landlab,SiccarPoint/landlab,landlab/landlab,Carralex/landlab,landlab/landlab,csherwood-usgs/landlab,csherwood-usgs/landlab,ManuSchmi88/landlab,cmshobe/landlab,cmshobe/landlab,cmshobe/landlab,amandersillinois/landlab,landlab/landlab,laijingtao/landlab,Carralex/landlab,Carralex/landlab,SiccarPoint/landlab,ManuSchmi88/landlab,amandersillinois/landlab,RondaStrauch/landlab,laijingtao/landlab,RondaStrauch/landlab,ManuSchmi88/landlab