Use transforms.getDescendantsOfType for safer vmerge removal

Author: mwilliamson

lib/docx/body-reader.js

@@ -567,7 +567,8 @@ function BodyReader(options) {
 
     function removeVMergeProperties(rows) {
         rows.forEach(function(row) {
-            row.children.forEach(function(cell) {
+            var cells = transforms.getDescendantsOfType(row, documents.types.tableCell);
+            cells.forEach(function(cell) {
                 delete cell._vMerge;
             });
         });