Wizard: Transform emtpy page data values to null

Previously the wizard wrote empty strings to config files.

library/Icinga/Web/Wizard.php

@@ -3,6 +3,7 @@
 
 namespace Icinga\Web;
 
+use Icinga\Forms\ConfigForm;
 use LogicException;
 use InvalidArgumentException;
 use Icinga\Web\Session\SessionNamespace;
@@ -286,7 +287,7 @@ class Wizard
 
                 if ($isValid) {
                     $pageData = & $this->getPageData();
-                    $pageData[$page->getName()] = $page->getValues();
+                    $pageData[$page->getName()] = ConfigForm::transformEmptyValuesToNull($page->getValues());
                     $this->setCurrentPage($this->getNewPage($requestedPage, $page));
                     $page->getResponse()->redirectAndExit($page->getRedirectUrl());
                 }

modules/setup/library/Setup/Utils/DbTool.php

@@ -121,6 +121,12 @@ class DbTool
      */
     public function __construct(array $config)
     {
+        if (! isset($config['port'])) {
+            // TODO: This is not quite correct, but works as it previously did. Previously empty values were not
+            //       transformed no NULL (now they are) so if the port is now null, it's been the empty string.
+            $config['port'] = '';
+        }
+
         $this->config = $config;
     }