swift234

[gyb] Provide Python 2 and 3 compatable exception syntax

In Python 2 the syntax to catch exceptions was:

except (Exception1, Exception2), target:

In Python 3 the syntax to catch exceptions is:

except (Exception1, Exception2) as target:

This newer Python 3 syntax is also available in 2.6 and 2.7. Therefore,
it is preferred for compatibility reasons. Additionally, the target no
longer can be a tuple. This patch refactors the exception handeling code
to be the newer Python 3 exception catch syntax.