[WordPress] Multisite: Restrict WP Rocket settings access to superadmins.

wp-rocket-user-role.php

<?php
/**
 * Plugin Name: WP Rocket User Role
 * Description: Restrict WP Rocket settings access to superadmins.
 * Version:     2015.12
 * Author:      Caspar Hübinger
 * Author URI:  https://profiles.wordpress.org/glueckpress/
 * Plugin URI:  http://docs.wp-rocket.me/article/129-change-user-role-for-wp-rocket-settings
 * License:     GNU General Public License v3
 * License URI: http://www.gnu.org/licenses/gpl-3.0.html
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

if ( ! function_exists( 'wprocket_userrole' ) && ! function_exists( 'wprocket_userrole__super_admin' ) ) {

	/**
	 * Load plugin.
	 */
	function wprocket_userrole() {
	
		add_filter( 'option_page_capability_wp_rocket', 'wprocket_userrole__super_admin' );
		add_filter( 'rocket_capacity', 'wprocket_userrole__super_admin' );
	}
	add_action( 'plugins_loaded', 'wprocket_userrole' );


	/**
	 * Set minimum capability to access WP Rocket settings.
	 * 
	 * @param  string $capability Minimum capability to access WP Rocket settings
	 * @return string             Minimum capability to access WP Rocket settings
	 */
	function wprocket_userrole__super_admin( $capability ) {
		
		if ( ! current_user_can( 'manage_network' ) ) {
			return 'manage_network';
		}
		
		return $capability;
	}
}