Break 1 level less, otherwise the rest of the messages are not processed.

I hit this bug by coincidance and thnx to a server crash. Cyrus returned
information like UID, RFC822.SIZE, INTERNALDATE (that info is probably
cached by cyrus) correct, but an empty header. At the end of the response
there was an untagged OK response with as server message: Message <nnn> no
longer exists.

functions/imap_messages.php

@@ -609,7 +609,7 @@ function sqimap_get_small_header_list ($imap_stream, $msg_list, $show_num=false)
             case 'BODY[HEADER.FIELDS':
                 $i = strpos($read,'{',$i);
                 $header = parseString($read,$i);
-                if ($header === false) break 3;
+                if ($header === false) break 2;
                 /* First we replace all \r\n by \n, and unfold the header */
                 $hdr = trim(str_replace(array("\r\n", "\n\t", "\n "),array("\n", ' ', ' '), $header));
                 /* Now we can make a new header array with */