Fix test for blocked.gif according to recent changes

tests/MailFunc.php

@@ -45,7 +45,7 @@ class MailFunc extends PHPUnit_Framework_TestCase
         $html = rcmail_html4inline(rcmail_print_body($part->body, $part, array('safe' => false)), 'foo');
 
         $this->assertRegExp('/src="'.$part->replaces['ex1.jpg'].'"/', $html, "Replace reference to inline image");
-        $this->assertRegExp('#background="./program/resources/blocked.gif"#', $html, "Replace external background image");
+        $this->assertRegExp('#background="program/resources/blocked.gif"#', $html, "Replace external background image");
         $this->assertNotRegExp('/ex3.jpg/', $html, "No references to external images");
         $this->assertNotRegExp('/<meta [^>]+>/', $html, "No meta tags allowed");
         //$this->assertNoPattern('/<style [^>]+>/', $html, "No style tags allowed");