[Patch] Missing second arg on substr

[Matt Bagley]

In the file 'post-by-email/include/Horde/Mime/Part.php' on line 2148 it has the wrong number of arguments:

$id = substr($id, $base_pos);

Since it appears we are checking from the beginning of the string, should be:

$id = substr($id, 0, $base_pos);

Great plugin!

[Kat Hagan]

Hi, thanks for this report. What version of PHP did that happen with?