index validity check looks dubious

Change-Id: Iccbbeab3b52d1d7369c19e333756713b42e83830
Reviewed-on: https://gerrit.libreoffice.org/61976Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sd/source/filter/eppt/pptx-epptooxml.cxx

@@ -1164,7 +1164,7 @@ void PowerPointExport::ImplWriteNotes(sal_uInt32 nPageNum)
                 .makeStringAndClear());
 
     // add slide implicit relation to notes
-    if (mpSlidesFSArray.size() >= nPageNum)
+    if (nPageNum < mpSlidesFSArray.size())
         addRelation(mpSlidesFSArray[ nPageNum ]->getOutputStream(),
                     oox::getRelationship(Relationship::NOTESSLIDE),
                     OUStringBuffer()