style(prometheus): remove commented test

pkg/tsdb/graphite/graphite_test.go

 package graphite
-
-// func TestGraphite(t *testing.T) {
-//
-// 	Convey("When executing graphite query", t, func() {
-// 		executor := NewGraphiteExecutor(&tsdb.DataSourceInfo{
-// 			Url: "http://localhost:8080",
-// 		})
-//
-// 		queries := tsdb.QuerySlice{
-// 			&tsdb.Query{Query: "{\"target\": \"apps.backend.*.counters.requests.count\"}"},
-// 		}
-//
-// 		context := tsdb.NewQueryContext(queries, tsdb.TimeRange{})
-// 		result := executor.Execute(queries, context)
-// 		So(result.Error, ShouldBeNil)
-//
-// 		Convey("Should return series", func() {
-// 			So(result.QueryResults, ShouldNotBeEmpty)
-// 		})
-// 	})
-//
-// }