[BUGFIX] Backend DateTimePicker has to use 24H format for time fields

DateTimePicker has to use the 24H format for time fields because
otherwise the AM/PM switch is not handled correctly.
It is already used for datetime fields but not for time/timesec fields.

Change-Id: Iaf83842e568bf822b07cccf74224f04be607d1d4
Resolves: #65975
Releases: master
Reviewed-on: http://review.typo3.org/38111


Reviewed-by: Andreas Fernandez <andreas.fernandez@aspedia.de>
Tested-by: Andreas Fernandez <andreas.fernandez@aspedia.de>
Reviewed-by: Benjamin Mack <benni@typo3.org>
Tested-by: Benjamin Mack <benni@typo3.org>