New graphite function removeEmptySeries

public/app/plugins/datasource/graphite/gfunc.js

@@ -603,6 +603,11 @@ function (_, $) {
     defaultParams: [5]
   });
 
+  addFuncDef({
+    name: 'removeEmptySeries',
+    category: categories.Filter
+  });
+
   addFuncDef({
     name: 'useSeriesAbove',
     category: categories.Filter,