Fix an incorrect debug() call (#219)

Fix an incorrect `debug()` call

Author: rwjblue

src/ember-app.js

@@ -389,8 +389,8 @@ class EmberApp {
     const currentSchemaVersion = FastBootSchemaVersions.latest;
     // set schema version to 1 if not defined
     schemaVersion = schemaVersion || FastBootSchemaVersions.base;
-    debug('Current schemaVersion from `ember-cli-fastboot` is %s while latest schema version is %s', (schemaVersion, currentSchemaVersion));
-
+    debug('Current schemaVersion from `ember-cli-fastboot` is %s while latest schema version is %s', schemaVersion, currentSchemaVersion);
+  
     if (schemaVersion > currentSchemaVersion) {
       let errorMsg = chalk.bold.red('An incompatible version between `ember-cli-fastboot` and `fastboot` was found. Please update the version of fastboot library that is compatible with ember-cli-fastboot.');
       throw new Error(errorMsg);