fix default data of calendar control Edit

previously html of this input element has space like
`value=" 2017-06-01 16:00 "`, but it should be `value="2017-06-01 16:00"`.

This pull request will fix #460 except for 'change date without click' problem.
I cannot find why this problem happens. Our code is almost same to [sample code](http://jqueryui.com/datepicker/).

So I think we have to keep #460 opened.