Graphite: added perSecond function to the func def list

src/app/services/graphite/gfunc.js

@@ -39,6 +39,13 @@ function (_) {
     defaultParams: [1],
   });
 
+  addFuncDef({
+    name: 'perSecond',
+    category: categories.Transform,
+    params: [],
+    defaultParams: [],
+  });
+
   addFuncDef({
     name: "holtWintersForecast",
     category: categories.Calculate,