fix #2763, change to lower case

src/pages/User/Login.js

@@ -114,7 +114,7 @@ class LoginPage extends Component {
             <Icon type="alipay-circle" className={styles.icon} theme="outlined" />
             <Icon type="taobao-circle" className={styles.icon} theme="outlined" />
             <Icon type="weibo-circle" className={styles.icon} theme="outlined" />
-            <Link className={styles.register} to="/User/Register">
+            <Link className={styles.register} to="/user/register">
               <FormattedMessage id="app.login.signup" />
             </Link>
           </div>

src/pages/User/Register.js

@@ -321,7 +321,7 @@ class Register extends Component {
             >
               <FormattedMessage id="app.register.register" />
             </Button>
-            <Link className={styles.login} to="/User/Login">
+            <Link className={styles.login} to="/user/login">
               <FormattedMessage id="app.register.sing-in" />
             </Link>
           </FormItem>