sd: fix closing document twice in testTdf118768.

Change-Id: I07def80070d8109b9d54ef19a841e3091f743b9c
Reviewed-on: https://gerrit.libreoffice.org/57791
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

sd/qa/unit/export-tests-ooxml2.cxx

@@ -1731,7 +1731,6 @@ void SdOOXMLExportTest2::testTdf118768()
     sd::DrawDocShellRef xDocShRef = loadURL(m_directories.getURLFromSrc("sd/qa/unit/data/odp/tdf118768-brake.odp"), ODP);
     utl::TempFile tempFile;
     xDocShRef = saveAndReload(xDocShRef.get(), PPTX, &tempFile);
-    xDocShRef->DoClose();
 
     // check that transition attribute didn't change from 'out' to 'in'
     xmlDocPtr pXmlDocContent = parseExport(tempFile, "ppt/slides/slide1.xml");