python: Explicitly add the 'L' suffix on Python 3

python: Explicitly add the 'L' suffix on Python 3

Python 2 had two integer types: int and long. Python 3 dropped the
latter, as it made the int type automatically support bigger numbers.

As a result, Python 3 lost the 'L' suffix on integer litterals.

This probably doesn't make much difference when compiling the generated
C code, but adding it explicitly means that both Python 2 and 3 generate
the exact same C code anyway, which makes it easier to compare and check
for discrepencies when moving to Python 3.

Signed-off-by: Mathieu Bridon <bochecha@daitauha.fr>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>