Unable to parse attachment which are email added as attachment

[GoogleCodeExporter]

Many Old version mail client add the previous emails as attachment with 
extension eml These attachments do not have any file name associated with it.

It throws and exception and exits

PHP Notice:  Undefined index: disposition-filename in MimeMailParser.class.php 
on line 245
PHP Fatal error:  Uncaught exception 'Exception' with message 'Could not create 
temporary files for attachments. Your tmp directory may be unwritable by PHP.' 
in MimeMailParser.class.php:448
Stack trace:
#0 MimeMailParser.class.php(247): MimeMailParser->getAttachmentStream(Array)
#1 email.php(125): MimeMailParser->getAttachments()
#2 {main}
  thrown in MimeMailParser.class.php on line 448

I m considering a patch whereby i provide a random file with extension eml in 
case disposition-filename is null

Original issue reported on code.google.com by [email protected] on 11 Feb 2012 at 1:49