coverity#705725: fix memory leak

Change-Id: I862ea9c4958497cc338b93bd0852c0b1494aee81

sot/source/sdstor/stgdir.cxx

@@ -883,6 +883,10 @@ void StgDirStrm::SetupEntry( sal_Int32 n, StgDirEntry* pUpper )
             SetupEntry( nRight, pUpper );
             SetupEntry( nLeaf, pCur );
         }
+        else
+        {
+            delete pCur;
+        }
     }
 }