python: Add function to raise exceptions from c.
python: Add function to raise exceptions from c.

* lang/python/helpers.c (pygpgme_raise_exception): New function.

Signed-off-by: Justus Winter <4d1bd7a5ca1cd26bee0df05b6801a6ce9a22196e@g10code.com>

gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme