Resolves: #i120021# fix memory leak in PptSlidePersistEntry dtor

Patch by: Chao Huang
Found by: Chao Huang
Review and minor modifications by: Herbert Duerr

Change-Id: I09e8b279e9cee63c33845744bc96ce13f202fa3c

filter/source/msfilter/svdfppt.cxx

@@ -498,6 +498,7 @@ PptSlidePersistEntry::PptSlidePersistEntry() :
 PptSlidePersistEntry::~PptSlidePersistEntry()
 {
     delete pStyleSheet;
+    delete pHeaderFooterEntry;
     delete pSolverContainer;
     delete[] pPresentationObjects;
 };