Don't use 'None' in displayPageHeader() calls

plugins/test/decodeheader.php

@@ -17,7 +17,7 @@ include_once(SM_PATH . 'functions/mime.php');
 
 global $oTemplate, $color;
 
-displayPageHeader($color, 'none');
+displayPageHeader($color, '');
 
 
 $header = array("< &  \xC3",                   // plain text

plugins/test/ngettext.php

@@ -16,7 +16,7 @@ include_once('../../include/init.php');
 
 global $oTemplate, $color;
 
-displayPageHeader($color, 'none');
+displayPageHeader($color, '');
 
 sq_change_text_domain('test');
 

plugins/test/test.php

@@ -14,7 +14,7 @@ include_once('../../include/init.php');
 
 global $oTemplate, $color;
 
-displayPageHeader($color, 'none');
+displayPageHeader($color, '');
 
 $oTemplate->display('plugins/test/test_menu.tpl');
 $oTemplate->display('footer.tpl');