fix(bulk-unordered): add check for ignoreUndefined

NODE-1155

Author: Jessica Lord

lib/bulk/unordered.js

@@ -463,6 +463,11 @@ var executeBatch = function(self, batch, callback) {
     finalOptions.serializeFunctions = true;
   }
 
+  // Ingore undefined
+  if (self.s.options.ignoreUndefined) {
+    finalOptions.ignoreUndefined = true;
+  }
+
   // Is the bypassDocumentValidation options specific
   if (self.s.bypassDocumentValidation === true) {
     finalOptions.bypassDocumentValidation = true;