convert last bits of String to OUString in svgio module

Change-Id: Ic056c83ba239e3c9066026a95d1b01d0b1fc5539

svgio/source/svgreader/svgimagenode.cxx

@@ -225,7 +225,7 @@ namespace svgio
 
                             if(GRFILTER_OK == GraphicFilter::GetGraphicFilter().ImportGraphic(
                                 aGraphic,
-                                String(),
+                                OUString(),
                                 aStream))
                             {
                                 extractFromGraphic(aGraphic, aNewTarget, aViewBox, aBitmapEx);