Fix comparison: if (d.clients === 0) return does nothing

lib/forcegraph.js

@@ -285,7 +285,7 @@ define(["d3"], function (d3) {
       ctx.beginPath()
       nodes.filter(visibleNodes).forEach(function (d) {
         var clients = d.o.node.statistics.clients
-        if (d.clients === 0)
+        if (clients === 0)
           return
 
         var distance = 16