writerfilter: remove never read m_xTableRange

Its last user was
writerfilter::dmapper::DomainMapperTableHandler::getTable(), removed in
commit 6ea66657ebca5b3ec63f93b496b812888e0d53c9 (loplugin:unusedmethods
writerfilter, 2015-07-20).

Change-Id: Ibaf536d4dd8f01f4413c3cec033db7438501e58c
diff --git a/writerfilter/source/dmapper/DomainMapperTableHandler.cxx b/writerfilter/source/dmapper/DomainMapperTableHandler.cxx
index 9cdfe1c..0b89aa1 100644
--- a/writerfilter/source/dmapper/DomainMapperTableHandler.cxx
+++ b/writerfilter/source/dmapper/DomainMapperTableHandler.cxx
@@ -1028,8 +1028,6 @@ void DomainMapperTableHandler::endTable(unsigned int nestedTableLevel, bool bTab

                if (xTable.is())
                {
                    m_xTableRange = xTable->getAnchor( );

                    if (!aMerges.empty())
                    {
                        // Perform horizontal merges in reverse order, so the fact that merging changes the position of cells won't cause a problem for us.
diff --git a/writerfilter/source/dmapper/DomainMapperTableHandler.hxx b/writerfilter/source/dmapper/DomainMapperTableHandler.hxx
index f779387..6097be3 100644
--- a/writerfilter/source/dmapper/DomainMapperTableHandler.hxx
+++ b/writerfilter/source/dmapper/DomainMapperTableHandler.hxx
@@ -65,8 +65,6 @@ class DomainMapperTableHandler final
    std::vector<CellSequence_t> m_aRowRanges;
    std::vector<RowSequence_t> m_aTableRanges;

    css::uno::Reference< css::text::XTextRange >           m_xTableRange;

    // properties
    PropertyMapVector2      m_aCellProperties;
    PropertyMapVector1      m_aRowProperties;