[FIX]web: Date in datepicker not comes selected by default when datep…

…icker is opened first time when date is set through onchange, it is because datepicker was not updating, bootstrap datetimepicker provides viewDate method to update the picker

addons/web/static/src/js/widgets/date_picker.js

@@ -63,7 +63,11 @@ var DateWidget = Widget.extend({
     },
     set_value_from_ui: function() {
         var value = this.$input.val() || false;
+        var previous_val = this.get('value');
         this.set_value(this.parse_client(value));
+        if (this.picker && value !== previous_val) {
+            this.picker.viewDate(value);
+        }
     },
     set_readonly: function(readonly) {
         this.readonly = readonly;