python: Fix distcheck.
* lang/python/Makefile.am (uninstall-local): Explicitly request the scheme 'posix_prefix'. On Python2.7 the default scheme is 'posix_local', breaking distcheck.
- Fixes-commit: 25e6444b3f4601c7821beab06bc4520deacb007b
- Signed-off-by: Justus Winter <justus@g10code.com>