Remove spurious #include from QJulianCalendar's implementation

The data tables are used to implement the locale-support methods,
which Julian inherits from Roman, so it doesn't need to access those
tables directly for itself - and doing so (potentially) duplicated
their static data in two compilation units.

Pick-to: 6.8 6.5 6.2
Task-number: QTBUG-128930
Change-Id: I313c14441c947daeb702aa17d85b4b6d4b5d3636
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/time/qjuliancalendar.cpp

@@ -3,7 +3,6 @@
 
 #include "qglobal.h"
 #include "qjuliancalendar_p.h"
-#include "qromancalendar_data_p.h"
 #include "qcalendarmath_p.h"
 
 #include <QtCore/qdatetime.h>