The newer "except <exception-type> as <exception>:" syntax is not
supported by Python 2.4, we need to use "except <exception-type>,
<exception>:".
Tested all trace backends with Python 2.4.
Reported-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>