MySQL may fall asleep during core extraction, so always try to wake it up

modules/system/classes/UpdateManager.php

@@ -1,5 +1,6 @@
 <?php namespace System\Classes;
 
+use Db;
 use App;
 use URL;
 use File;
@@ -415,6 +416,9 @@ class UpdateManager
 
         @unlink($filePath);
 
+        // Database may fall asleep after this long process
+        Db::reconnect();
+
         Parameters::set([
             'system::core.hash'  => $hash,
             'system::core.build' => $build