fix FormControl update conflicting with date picker
fix FormControl update conflicting with date picker

ng2-ui/datetime-picker,ng2-ui/ng2-datetime-picker,ng2-ui/datetime-picker,jsvalley/ng2-datetime-picker,jsvalley/ng2-datetime-picker,ng2-ui/ng2-datetime-picker,jsvalley/ng2-datetime-picker,jsvalley/ng2-datetime-picker,ng2-ui/datetime-picker,ng2-ui/ng2-datetime-picker