Fix crash in S60 input methods after task switching
Fix crash in S60 input methods after task switching

When switching away from the application, the focused widget is set to
null. When switching back, there are callbacks from S60 before the focus
has been restored.
These functions check for null widget, but the output function parameters
are left uninitialised, which causes a crash inside the S60 FEP.
1) GetXYZ functions now initialise the output parameters even when the
   focused widget is null.
2) Return no input capability when there is no focused widget, as was
   already done during destruction. This stops most of the callbacks
   from S60.

Task-number: QTBUG-4618
Reviewed-by: axis

igor-sfdc/qt-wk,igor-sfdc/qt-wk,igor-sfdc/qt-wk,igor-sfdc/qt-wk,radekp/qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,radekp/qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,radekp/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,radekp/qt,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt