rm bar (now useless) 'placeholder' logic

- see #1369
  for why that was needed.

Author: etpinard

src/traces/bar/set_positions.js

@@ -38,8 +38,7 @@ module.exports = function setPositions(gd, plotinfo) {
             fullTrace.visible === true &&
             Registry.traceIs(fullTrace, 'bar') &&
             fullTrace.xaxis === xa._id &&
-            fullTrace.yaxis === ya._id &&
-            !calcTraces[i][0].placeholder
+            fullTrace.yaxis === ya._id
         ) {
             if(fullTrace.orientation === 'h') {
                 calcTracesHorizontal.push(calcTraces[i]);

test/jasmine/tests/bar_test.js

@@ -703,23 +703,6 @@ describe('Bar.setPositions', function() {
         expect(Axes.getAutoRange(ya)).toBeCloseToArray([-1.11, 1.11], undefined, '(ya.range)');
     });
 
-    it('should skip placeholder trace in position computations', function() {
-        var gd = mockBarPlot([{
-            x: [1, 2, 3],
-            y: [2, 1, 2]
-        }, {
-            x: [null],
-            y: [null]
-        }]);
-
-        expect(gd.calcdata[0][0].t.barwidth).toEqual(0.8);
-
-        expect(gd.calcdata[1][0].x).toBe(false);
-        expect(gd.calcdata[1][0].y).toBe(false);
-        expect(gd.calcdata[1][0].placeholder).toBe(true);
-        expect(gd.calcdata[1][0].t.barwidth).toBeUndefined();
-    });
-
     it('works with log axes (grouped bars)', function() {
         var gd = mockBarPlot([
             {y: [1, 10, 1e10, -1]},