Do not set current moment when opening the picker

Otherwise this trigger a display before the focus out of the previously focused
widget. Such that the previous widget may loose its data.
So we prevent datetimepicker to set a moment and such that it behaves like
tryton.

issue8921
review266581003

src/view/form.js

@@ -1403,6 +1403,7 @@ function eval_pyson(value){
             this.date.datetimepicker({
                 'locale': moment.locale(),
                 'keyBinds': null,
+                'useCurrent': false,
             });
             this.date.css('max-width', this._width);
             this.date.on('dp.change', this.focus_out.bind(this));
@@ -4515,6 +4516,7 @@ function eval_pyson(value){
                 'format': Sao.common.moment_format(this.format),
                 'locale': moment.locale(),
                 'keyBinds': null,
+                'useCurrent': false,
             });
             this.date.on('dp.change',
                     this.parent_widget.focus_out.bind(this.parent_widget));