Set time to midnight as described in #4115

Set time to midnight on date types. 
Prevents behaviour described in http://php.net/manual/en/datetime.createfromformat.php#110385
Returning $date

Maybe this fixes the error?
Merge pull request #4119 from Hikkijp/patch-1

Set time to midnight as described in #4115

Fixes issues where date type columns would always reflect the current time.

Fixes #4115