remove unnecessary properties in format function

lib/cartodb/models/dataview/numeric-histogram.js

@@ -261,9 +261,6 @@ module.exports = class NumericHistogram extends BaseDataview {
         var infinities = 0;
         var nans = 0;
         var avg;
-        var timestampStart;
-        var aggregation;
-        var offset;
 
         if (result.rows.length) {
             var firstRow = result.rows[0];
@@ -271,23 +268,14 @@ module.exports = class NumericHistogram extends BaseDataview {
             width = firstRow.bin_width || width;
             avg = firstRow.avg_val;
             nulls = firstRow.nulls_count;
-            timestampStart = firstRow.timestamp_start;
             infinities = firstRow.infinities_count;
             nans = firstRow.nans_count;
             binsStart = this.populateBinStart(override, firstRow);
 
-            if (Number.isFinite(timestampStart)) {
-                aggregation = this.getAggregation(override);
-                offset = this.getOffset(override);
-            }
-
             buckets = result.rows.map(row => ({ bin, min, max, avg, freq } = row));
         }
 
         return {
-            aggregation: aggregation,
-            offset: offset,
-            timestamp_start: timestampStart,
             bin_width: width,
             bins_count: binsCount,
             bins_start: binsStart,