docx export: explicitely use 'none' type for disabled cell borders

Otherwise, the table default borders will be used.

Change-Id: Iebab1204dc40f79e10164e4815bbdbbe054ef144
Reviewed-on: https://gerrit.libreoffice.org/909Reviewed-by: Miklos Vajna <vmiklos@suse.cz>
Tested-by: Miklos Vajna <vmiklos@suse.cz>

sw/source/filter/ww8/docxattributeoutput.cxx

@@ -1349,7 +1349,7 @@ static void impl_borderLine( FSHelperPtr pSerializer, sal_Int32 elementToken, co
     //      thickThinMediumGap, thickThinLargeGap, thickThinSmallGap
     //      thinThickLargeGap, thinThickMediumGap, thinThickSmallGap
     const char* pVal = "none";
-    if ( !pBorderLine->isEmpty( ) )
+    if ( pBorderLine && !pBorderLine->isEmpty( ) )
     {
         switch (pBorderLine->GetBorderLineStyle())
         {
@@ -1403,7 +1403,7 @@ static void impl_borderLine( FSHelperPtr pSerializer, sal_Int32 elementToken, co
 
     pAttr->add( FSNS( XML_w, XML_val ), OString( pVal ) );
 
-    if ( !pBorderLine->isEmpty() )
+    if ( pBorderLine && !pBorderLine->isEmpty() )
     {
         // Compute the sz attribute
 
@@ -1452,9 +1452,7 @@ static void impl_pageBorders( FSHelperPtr pSerializer, const SvxBoxItem& rBox, s
     for( int i = 0; i < 4; ++i, ++pBrd )
     {
         const SvxBorderLine* pLn = rBox.GetLine( *pBrd );
-        if ( pLn )
-        {
-            if ( pDefaultBorders )
+        if ( pDefaultBorders && pLn )
         {
             const SvxBorderLine* pRefLn = pDefaultBorders->GetLine( *pBrd );
 
@@ -1479,7 +1477,6 @@ static void impl_pageBorders( FSHelperPtr pSerializer, const SvxBoxItem& rBox, s
                 impl_borderLine( pSerializer, XML_insideV, pLn, 0 );
         }
     }
-    }
     if (tagWritten && bWriteTag) {
         pSerializer->endElementNS( XML_w, tag );
     }