Fixed error message during install due to missing database tables

Author: rexblack

mu-loader.php

@@ -2,6 +2,12 @@
 
 function mu_loader_plugins_files()
 {
+  
+    if (defined('WP_INSTALLING') && WP_INSTALLING === true) {
+      // Do nothing during installation
+      return array();
+    }
+  
     // Cache plugins
     $plugins = get_site_transient('mu_loader_plugins');