Change default value for disableDirectivesChecking to false as mentioned in #107 (comment)

Author: rcapshaw

graphql-server/drivers/arangodb/driver.js

@@ -66,7 +66,7 @@ async function init(args) {
     let dbName = args.dbName || 'dev-db';
     let url = args.url || 'http://localhost:8529';
     let drop = args.drop || false;
-    disableDirectivesChecking = args['disableDirectivesChecking'] || true;
+    disableDirectivesChecking = args['disableDirectivesChecking'] || false;
     disableEdgeValidation = args['disableEdgeValidation'] || false;
     db = new arangojs.Database({ url: url });