writerfilter: avoid exception - IsProtect not page style property.

Change-Id: I3e91bc82e5857116f5d94103a7c22ce333e4f89b
Reviewed-on: https://gerrit.libreoffice.org/65976
Tested-by: Jenkins
Reviewed-by: Justin Luth <justin_luth@sil.org>

writerfilter/source/dmapper/PropertyMap.cxx

@@ -1730,7 +1730,9 @@ void SectionPropertyMap::ApplyProperties_( const uno::Reference< beans::XPropert
 
         for ( beans::PropertyValue* pIter = vPropVals.begin(); pIter != vPropVals.end(); ++pIter )
         {
-            if ( pIter != pCharGrabBag && pIter != pParaGrabBag )
+            if ( pIter != pCharGrabBag && pIter != pParaGrabBag
+                 && pIter->Name != "IsProtected" //section-only property
+               )
             {
                 vNames.push_back( pIter->Name );
                 vValues.push_back( pIter->Value );