Fix the server startup messages and help text. (#3211)

cmd/post-policy_test.go

@@ -109,7 +109,7 @@ func testPostPolicyHandler(obj ObjectLayer, instanceType string, t TestErrHandle
 	if err != nil {
 		t.Fatalf("Init Test config failed")
 	}
-	// remove the root folder after the test ends.
+	// remove the root directory after the test ends.
 	defer removeAll(rootPath)
 
 	credentials := serverConfig.GetCredential()