fixed warning

src/view_text.php

@@ -46,7 +46,8 @@
          "</TD></TR></TABLE>".
          "<TABLE WIDTH=\"98%\" BORDER=0 CELLSPACING=0 CELLPADDING=2 ALIGN=CENTER><TR><TD BGCOLOR=\"$color[0]\">".
          "<TR><TD BGCOLOR=\"$color[4]\"><TT>";
-    if ($type1 == 'html' || $override_type1 == 'html') {
+    if ($type1 == 'html' || 
+         (isset($override_type1) &&  $override_type1 == 'html')) {
         $body = MagicHTML( $body, $passed_id, $message, $mailbox);
     } else {
         translateText($body, $wrap_at, $charset);