Added d3 force graph to GUI2 topology

Change-Id: I6860472efaf51ea27fad74e630e687f0c6abad3d
diff --git a/web/gui2/src/main/webapp/app/view/topology/layer/backgroundsvg/backgroundsvg.component.ts b/web/gui2/src/main/webapp/app/view/topology/layer/backgroundsvg/backgroundsvg.component.ts
index ff6f99a..e07f304 100644
--- a/web/gui2/src/main/webapp/app/view/topology/layer/backgroundsvg/backgroundsvg.component.ts
+++ b/web/gui2/src/main/webapp/app/view/topology/layer/backgroundsvg/backgroundsvg.component.ts
@@ -44,6 +44,7 @@
  * Enum of the topo2CurrentRegion location type from Location below
  */
 export enum LocationType {
+    NONE = 'none',
     GEO = 'geo',
     GRID = 'grid'
 }