WaE: ´nLen´ may be used uninitialized in this function

Looking at the change to this line in e904749e
, I think this line was changed incorrectly. So I won't simply "fix" the
warninig by initialising nLen to some value like zero, but instead reinstate
the use of the nCharCount2 here instead of nLen.

Change-Id: Ice4a5cb751a244c38b3cfc4e05e3206cb939484a

filter/source/msfilter/svdfppt.cxx

@@ -5195,7 +5195,7 @@ void PPTStyleTextPropReader::Init( SvStream& rIn, SdrPowerPointImport& rMan, con
                 }
                 else
                 {
-                    aCharPropSet.maString = aString.copy(nCharAnzRead, nLen);
+                    aCharPropSet.maString = aString.copy(nCharAnzRead, nCharCount);
                     aCharPropList.push_back( new PPTCharPropSet( aCharPropSet, nCurrentPara ) );
                     nCharAnzRead += nCharCount;
                     bEmptyParaPossible = sal_False;