webadmin: Changed DateFormatCompat class in uioverrides to DateFormat

Changed the DateFormatCompat class in uioverride to java.text.DateFormat
this class takes the date format types in DateFormat anyway and the equivalent
class DateFormatCompat in the compat module was removed so no point in keeping
the old class name

Change-Id: I345a36a2512f8240e739a6c190aaa5f0cf020940
Signed-off-by: Tal Nisan <tnisan@redhat.com>