python: Trim imports.
* lang/python/examples/encrypt-to-all.py: Drop unused import of 'os'. * lang/python/examples/signverify.py: Likewise. * lang/python/examples/simple.py: Likewise. * lang/python/examples/verifydetails.py: Likewise.
- Signed-off-by: Justus Winter <justus@g10code.com>