package/{avro-c, python-avro}: bump to version 1.11.0

- Drop avro-c patch (already in version)
- Drop python-avro patch (not needed anymore)

https://github.com/apache/avro/releases/tag/release-1.11.0



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>