code: void removeInVertexLabel(VertexLabel lbl, boolean preserveData) {
          this.uncommittedRemovedInVertexLabels.add(lbl);
          if (!preserveData) {
              deleteColumn(lbl.getFullName() + Topology.IN_VERTEX_COLUMN_END);
          }
      }
docs: remove a vertex label from the in collection
  
  @param lbl          the vertex label
  @param preserveData should we keep the sql data?