python: Make 'get_key' more idiomatic.
* lang/python/pyme/core.py (Context.get_key): Raise errors.KeyNotFound if the key is not found. This error is both a KeyError for idiomatic error handling as well as a GPGMEError so we don't break existing code. * lang/python/pyme/errors.py (KeyNotFound): New class. * lang/python/tests/support.py (no_such_key): New variable. * lang/python/tests/t-keylist.py: Test the new behavior.
- Signed-off-by: Justus Winter <justus@g10code.com>