remove unused local vars

since commit 95c348afa8
    loplugin:unusedfields in svx part2

Change-Id: I6d5f3704f4efef0a9fb69623f46a216c509c8302
Reviewed-on: https://gerrit.libreoffice.org/39229
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Jochen Nitschke <j.nitschke+logerrit@ok.de>

svx/source/svdraw/svdibrow.cxx

@@ -446,13 +446,8 @@ void SdrItemBrowserControl::ImpSaveWhich()
 {
     sal_uInt16 nWh=GetCurrentWhich();
     if (nWh!=0) {
-        long nPos=GetCurrentPos();
-        long nTop=GetTopRow();
-        long nBtm=GetTopRow()+GetVisibleRows()+1;
         nLastWhich=nWh;
-        nLastWhichOfs=nPos-nTop;
-        if (nTop<0) nTop=0;
-        if (nBtm>=(long)aList.size()) nBtm=aList.size()-1;
+        nLastWhichOfs=GetCurrentPos()-GetTopRow();
     }
 }