MAGETWO-61209: Fixed issue with mage/calendar when setting numberOfMonths to show more than 1 month

(cherry picked from commit 54e1a71)

Author: Vasilii Burlacu

lib/web/mage/calendar.js

@@ -236,12 +236,14 @@
                 firstDay = parseInt(this._get(inst, 'firstDay'), 10);
                 firstDay = isNaN(firstDay) ? 0 : firstDay;
 
-                for (row; row < numMonths[0]; row++) {
+                for (row = 0; row < numMonths[0]; row++) {
                     this.maxRows = 4;
 
-                    for (col; col < numMonths[1]; col++) {
+                    for (col = 0; col < numMonths[1]; col++) {
                         selectedDate = this._daylightSavingAdjust(new Date(drawYear, drawMonth, inst.selectedDay));
 
+                        calender = '';
+
                         if (isMultiMonth) {
                             calender += '<div class="ui-datepicker-group';
 
@@ -271,7 +273,7 @@
                         thead = showWeek ?
                             '<th class="ui-datepicker-week-col">' + this._get(inst, 'weekHeader') + '</th>' : '';
 
-                        for (dow; dow < 7; dow++) { // days of the week
+                        for (dow = 0; dow < 7; dow++) { // days of the week
                             day = (dow + firstDay) % 7;
                             thead += '<th' + ((dow + firstDay + 6) % 7 >= 5 ?
                                 ' class="ui-datepicker-week-end"' : '') + '>' +
@@ -289,7 +291,7 @@
                         this.maxRows = numRows;
                         printDate = this._daylightSavingAdjust(new Date(drawYear, drawMonth, 1 - leadDays));
 
-                        for (dRow; dRow < numRows; dRow++) { // create date picker rows
+                        for (dRow = 0; dRow < numRows; dRow++) { // create date picker rows
                             calender += '<tr>';
                             tbody = !showWeek ? '' : '<td class="ui-datepicker-week-col">' +
                             this._get(inst, 'calculateWeek')(printDate) + '</td>';