fix datesDisabled
fix datesDisabled

"this" refers the wrong object
davidpatters0n/bootstrap-datetimepicker,davidpatters0n/bootstrap-datetimepicker,AuspeXeu/bootstrap-datetimepicker,smalot/bootstrap-datetimepicker,AuspeXeu/bootstrap-datetimepicker,smalot/bootstrap-datetimepicker,smalot/bootstrap-datetimepicker,davidpatters0n/bootstrap-datetimepicker,AuspeXeu/bootstrap-datetimepicker