fix version_compare (why did this work for me in the first place?); fix fallback if user still has 'classic' as theme

Signed-off-by: Michael Kaufmann (d00p) <d00p@froxlor.org>

lib/init.php

@@ -363,11 +363,16 @@ $theme = isset($settings['panel']['default_theme']) ? $settings['panel']['defaul
 /**
  * overwrite with customer/admin theme if defined
  */
-if(isset($userinfo['theme']) && $userinfo['theme'] != $theme)
-{
+if (isset($userinfo['theme']) && $userinfo['theme'] != $theme) {
 	$theme = $userinfo['theme'];
 }
 
+// check for existence of the theme
+if (!file_exists('templates/'.$theme.'/index.tpl')) {
+	// Fallback
+	$theme = 'Froxlor';
+}
+
 /*
  * check for custom header-graphic
  */