Fixed _split_link_ends to work with one link.
Fixed _split_link_ends to work with one link.

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