Fix so plain text signature field uses monospace font (#1490435)

Aleksander Machniak

2015-06-17 3f4521bcf4b538b6ac54817cfad22b51e347546d

 program/include/rcmail_output_html.php

@@ -584,7 +584,7 @@
        // read template file
        if (!$path || ($templ = @file_get_contents($path)) === false) {
            rcube::raise_error(array(
                'code' => 501,
                'code' => 404,
                'type' => 'php',
                'line' => __LINE__,
                'file' => __FILE__,