minor assertion

git-svn-id: file:///home/shish/svn/shimmie2/trunk@111 7f39781d-f577-437e-ae19-be835c7a54ca

core/util.inc.php

@@ -161,6 +161,8 @@ function get_memory_limit() {
 		$memory = $default_limit; 
 	}
 
+	assert($memory > 0);
+
 	return $memory;
 }