docx: actually import the last frame of a section.

When there is no paragraph outside the frame before the section end, the
paragraphs weren't transformed to a frame.

writerfilter/source/dmapper/DomainMapper.cxx

@@ -3233,6 +3233,7 @@ void DomainMapper::lcl_startParagraphGroup()
 
 void DomainMapper::lcl_endParagraphGroup()
 {
+    m_pImpl->CheckUnregisteredFrameConversion();
     m_pImpl->PopProperties(CONTEXT_PARAGRAPH);
     m_pImpl->getTableManager().endParagraphGroup();
     //frame conversion has to be executed after table conversion

writerfilter/source/dmapper/DomainMapper_Impl.hxx

@@ -578,6 +578,7 @@ public:
     void SetCustomFtnMark(bool bSet) { m_bIsCustomFtnMark = bSet; }
     bool IsCustomFtnMark() const { return m_bIsCustomFtnMark;  }
 
+    void CheckUnregisteredFrameConversion( );
     void RegisterFrameConversion(
         ::com::sun::star::uno::Reference< ::com::sun::star::text::XTextRange > xFrameStartRange,
         ::com::sun::star::uno::Reference< ::com::sun::star::text::XTextRange > xFrameEndRange,