fixed recent fix of splitVertices to handle case with var2vertexID is all NAs
fixed recent fix of splitVertices to handle case with var2vertexID is all NAs

nimble-dev/nimble,NLMichaud/nimble,nxdao2000/nimble,nimble-dev/nimble,nimble-dev/nimble,NLMichaud/nimble,nxdao2000/nimble,nimble-dev/nimble,NLMichaud/nimble,nxdao2000/nimble,nxdao2000/nimble,nimble-dev/nimble,NLMichaud/nimble