A last-minute fixup when applying 5527266559 (package/python-avro:
don't refer to avro-c version variable) improperly duplicated the exact
same comment as in avro-c. Of course, we want to refer to avro-c from
python-avro...
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>